Lewis Hamilton finished third, with Max Verstappen picking up damage that dropped him out of the lead fight early in the restarted race, which was stopped after just a few corners due to the Turn 1 incident.
At the start of the race, Verstappen used the grip advantage of soft tyres against the mediums on pole-sitting Sainz’s Ferrari to get alongside off the line and steal ahead into Abbey to immediately wrestle the lead from second on the grid, while Hamilton rocketed past Perez and Leclerc to take third from fifth.
As Leclerc was making an attempt to get back ahead of the Mercedes through Village and the Loop a couple of corners later, the race was red-flagged due to the multi-car pile-up behind the leaders at Abbey.
On the approach to the rapid right first corner, contact between Pierre Gasly and George Russell to speared the Mercedes into the side of the Alfa Romeo driver Zhou Guanyu, which flipped it over.
Zhou slid at high speed into the gravel upside down and in horrifying scenes bounced over the tyre barrier beyond, with the Chinese driver’s wrecked car coming to rest between the catch fence protecting the grandstand just behind and the back of the barrier.
It took several minutes to get Zhou out, but fortunately he was conscious and taken to the track medical centre.
Williams driver Alex Albon was also transported there as he was the first driver to be caught up in a secondary incident after Zhou and Russell were eliminated. Gasly was able to carry on relatively unscathed.
As the following Valtteri Bottas slowed, his car being showered with debris, Albon braked hard too and was rear-ended by Sebastian Vettel’s Aston Martin, which spun the Williams into the wall and he then hit the front-right of Alpine driver Esteban Ocon and then as a result of that third impact struck Yuki Tsunoda in the other AlphaTauri.
All of those drivers bar Albon were able to recover to the pits for repairs, with the race suspended for 53 minutes, during which it was announced that several protesters had invaded the track shortly down the Wellington straight at the same time as the original start before quickly being removed.
When it did resume, the order – other the three cars that did not take the restart – was the same as the initial grid.
This was because the pack had not passed the second safety car line at the end of lengthy pit lane exit by the time the race was stopped and in such circumstances the FIA must take the order from last point it can determine the order, which is back to what it was before the lights had gone out.
This time, with Verstappen now matching the Ferrari cars on the medium tyres, the Red Bull again made a better getaway and was quickly alongside Sainz, who squeezed the Dutchman close to the pitwall.
But with Verstappen not backing down, Sainz was forced to hang on around the outside of Abbey but did so to thrillingly retain the lead, with Leclerc again making a slow getaway behind the two leaders, this time with Perez getting by off the line.
But Leclerc sent a bold move to Perez’s inside at Turn 4 and was able to force his way back to third, with the Monegasque driver then getting such good drive onto the Wellington straight he was able to attack Verstappen at Brooklands.
There, with Leclerc obliged by Verstappen to take the outside line, the pair clashed lightly and the Ferrari had to take to the runoff before his right-front wing endplate, which was damaged in the earlier contact with Perez, flying off on the run to Copse and hitting the second Red Bull’s front wing right-side and causing similar harm.
That would soon mean Perez had to pit for a new wing, which released the battling Hamilton and Lando Norris, while up front Sainz had established a lead over a second by the time the DRS was activated on lap five of 52.
It took Verstappen a few laps before he was able to edge his way back into the critical one-second window, after which he was able to put Sainz under considerable pressure.
On lap 10, Sainz had to catch a massive oversteer snap through Becketts and was snapped off track briefly, which allowed Verstappen to sweep ahead down the Hangaer straight.
Verstappen quickly shot to a lead above one second, but his lead only lasted two laps as he was then slow through Maggotts and Becketts with what he suspected was a puncture picked up after running over the kerbs at Copse on lap 12, but which Red Bull later explained was damage to a small winglet at the rear of his car.
Verstappen immediately pitted for another set of mediums, Sainz having already moved back to the lead and Leclerc threatening, with Hamilton not far behind after he had dispatched Norris into Brooklands on the lap after Perez stopped early on.
That put Verstappen out of contention, with Sainz soon coming under pressure from Leclerc despite the second Ferrari’s damaged front wing, the gap down to 0.9s by lap 14.
Leclerc was so close that Sainz decided to move down the Hangar straight, with the chasing Ferrari soon insisting he was quicker and urging Ferrari to do something about the situation.
With Ferrari opting to leave things alone, Hamilton was soon homing in on the pair and was just under four seconds behind when Sainz was called in to ease Ferrari’s quandary at the end of lap 20 to take the hards.
Leclerc therefore led for the next five laps before he pitted, having been shipping a few tenths each time to the charging Hamilton behind.
Mercedes did not immediately move to bring its remaining car in, opting to build a tyre off-set while Leclerc, having passed the difficult tyre warm-up phase on the white-walled rubber that Sainz had already got through, again closed in on his teammate.
Ferrari gave Sainz the chance to lift his pace, but decided he could not run fast enough and so on lap 31 ordered the Spaniard to let his teammate by.
After this, Leclerc edged clear to lead by just under a second, but was matching Hamilton’s times up front and so on lap 33 the Briton was called in to make his switch to the hards, but a getting his used left-front medium off took slightly longer than normal and so it ended up being a 4.3s stop that meant he came out behind the two red cars.
Leclerc began pulling away from Sainz, who had been warned he need to save fuel, to his frustration, with the gap between the pair reaching 3.5s at the end of lap 38.
But on the next tour, Ocon, who had just overtaken Verstappen for eighth with the Red Bull having made a second stop to take hards, which he felt made his hobbled car worse, slowed down the national pits straight.
Ocon stopped before Copse and the safety car was therefore called out, with Ferrari leaving Leclerc out on his aging hards despite appearing to have time to call him in, as it did for Sainz and Mercedes did for Hamilton.
That closed the pack up, with Perez, who had been displaying strong pace after his early first stop, therefore suddenly a factor again in fourth.
Ferrari urged Sainz, who like all the frontrunners bar Leclerc would see out the race on the softs, to drop back at the restart within the allowed 10 car lengths to give the lead “breathing space”, a call he swiftly rejected.
On the restart tour on lap 43, Leclerc lost momentum going wide out of Aintree and onto the Wellington straight, with Sainz blasting back to the lead after seeing off his teammate’s attentions at Brooklands.
Sainz steamed clear, with Leclerc running ahead of Perez, who had dispatched the seemingly grip-less Hamilton as they ran through Aintree behind the battling Ferraris.
On lap 45, with Sainz clear ahead by 2.3s, Leclerc slid through Luffield and Perez was all over his rear, the Mexican staying close and then making a late, bold dive on the inside line at Stowe.
But Leclerc hung on and they went side-by-side through the first two parts of Club, with Perez appearing to go off track exiting the second apex and Hamilton therefore nipping ahead of both through the final part running onto the Hamilton straight opposite the pits.
Perez then forcefully repassed the Mercedes at Village on the next lap and shot clear to chase Sainz, which ended up fruitless as the Ferrari driver held on to take his first F1 win by 3.7s.
The action was not over however, as on lap 47 Hamilton went around Leclerc’s outside all the way around Luffield to run third by the time they reached Woodcote.
But Leclerc did not give up and somehow took his much older hards to get a run on the outside of Copse, where he repassed Hamilton in a stunning move.
It was all for nothing as Hamilton blasted by with DRS on the subsequent run down the Hangar straight, with the home hero going on to finish 6.2s behind Sainz.
Leclerc was able to defy the closely-following Fernando Alonso and Norris, both of whom had stopped under the safety car as well, to the finish in fourth, fifth and six.
Verstappen came home seventh after likewise getting a safety car stop for softs and he saw off the close attentions of Mick Schumacher.
The Haas driver had a look to the inside of Stowe with a couple of laps remaining and then nearly hit Verstappen with a bold move at the first part of Club on the final tour before backing out of certain contact at the final corner just a few moments later.
That decision meant Schumacher scored his first F1 points in eighth ahead of mentor Vettel and teammate Kevin Magnussen.
The other retirees were Gasly and Valtteri Bottas, who both stopped in the pits during the middle phase of the race, the former having early been spun around at Village when teammate Tsunoda lost the rear of his car in a move to the inside, for which the Japanese driver was given a five-second time addition penalty.
Tsunoda finished last behind the other remaining runners Lance Stroll, Nicholas Latifi and Daniel Ricciardo.
The late passes between Perez and Leclerc and Perez and Hamilton were noted by the stewards by were deemed not worthy of investigating.