Hamilton started second alongside Bottas in a Mercedes front-row lockout after being bested by 0.6 seconds during qualifying, but the Briton scythed down the inside of the slow-starting Finn at lights-out to lead the race.
The reigning world champion set the pace of the race from there, and with Mercedes holding a comfortable performance advantage over the rest of the field, Hamilton was free to lead home the team’s fifth one-two finish and a bonus point for fastest lap, earning him a seven-point advantage in the title standings.
“I just have to put it down to this incredible team,” Hamilton said. “This is history in the making to have five one-twos, so I’m very proud to be a part of that and proud of everyone’s hard work.”
Bottas was able to only just keep touch with Hamilton for most of the race, but the Finn blamed a clutch problem for undermining his start and costing him victory.
“There was some strange behaviour of the clutch — it was biting, releasing, biting, releasing — which I never felt before,” he said. “I lost it there.
“I got some good points — every single point is going to count this year — but I’m just keen to find out why the start was so bad and why the issue happened.”
Red Bull Racing’s Max Verstappen rounded out the podium after cutting past Sebastian Vettel on a fraught first lap. Ferrari spent the race trying to recover the position with strategy, but the Dutchman’s pace was enough to neutralise the threat and score his second podium of the season.
“Of course the Mercedes cars were too quick today, but I could do my own pace,” he said. “We were competitive and I could get myself on the podium.”
The result was particularly painful for Ferrari, which pegged the Spanish Grand Prix as an acid test for promises made by its strong preseason testing form at the same Barcelona circuit. It came up short in both qualifying and the race and now trails Mercedes by 96 points, with drivers Vettel and Charles Leclerc 48 and 55 points respectively in arrears.
Its race was effectively finished at the first turn when Vettel, attempting to hang on to Bottas’s outside in a strike for the lead, locked up and slid off the track. He almost cut off teammate Leclerc as he rejoined, and the pair’s lost momentum opened the door for Verstappen to breeze past into third.
The Scuderia duo uncomfortably squabbled in the opening phase of the race, with Vettel ahead struggling on his flat-spotted tyre. He was eventually ordered to let Leclerc through, and his team put him on a two-stop strategy to compensate.
It turned out to be the better way forward, and in the second stint Ferrari was forced to order Leclerc to let Vettel back past, the Monegasque by then on a slower-one stop strategy on the hard tyre. Mercedes, serenely leading the race, had enough pace in hand to finish the race with one or two stops.
Bu the unfolding tactical picture for the podium battle was neutralised on lap 46 when Lando Norris clumsily punted Lance Stroll off the road in a botched overtaking attempt at turn one, sending both cars into the gravel and triggering a safety car.
The caution lasted until lap 53, generating a 13-lap dash for the flag, but the fight for the podium was staid, with the top four position remaining unthreatened to the chequer. Only Leclerc was forced into a fight, the Monegasque required to defend his fifth place from Pierre Gasly and his softer tyres for half a lap before regaining control.
Haas teammates Kevin Magnussen and Romain Grosjean caused some brief fireworks, colliding at turn one as they ran side by side, with the latter forced to run off the track to avoid further damage. The Frenchman then came under attack from McLaren’s Carlos Sainz and Daniil Kvyat, who demoted him 10th in the final laps of the race.