The victory bodes well for Mercedes for the rest of the season as the performances in Barcelona - where most teams bring significant vehicle updates - usually set the tone for the rest of the races on the European portion of the calendar.
But Mercedes, who pitted some 10 laps earlier than the two Red Bulls, managed their tyres to the finish, while Vettel's hopes were futher dashed by his own slow second stop under the virtual safety vehicle. Ferrari was attempting to cover off Valtteri Bottas behind, who may have tried to undercut him by pitting earlier, but Vettel's early stop tied him to a one-stop for the rest of the race.
But Ferrari brought him in for a second pitstop when the virtual safety vehicle appeared just past half-distance, dropping Vettel from second to fourth.
His teammate Valtteri Bottas completed over 20 seconds behind with Crimson Bull's Max Verstappen finishing the rostrum.
That will certainly be nice for Ferrari to hear, considering the criticism that followed the decision.
"It is a constant learning process but these tires they seem to have a small working window whether they give us more rubber or less rubber they appear to be a lot harder than past year even though they went softer".
Rashford told to dump Man Utd after West Ham snub
But the Red Devils still have a last throw of the dice when they face Chelsea in the FA Cup final at the same venue. United are playing an terrible brand of football , not as poor as Van Gaal's but still frightful to watch.
"Obviously it looks different and looks wrong but it was the right thing to do". Hamilton has two of those wins (2014 and 2017), as well as six overall podium finishes in 11 starts, and he is understandably the favorite to make it back-to-back this weekend.
"I think today has been a rejuvenating experience", he said.
For Hamilton, it was a relief to finally win his first pole since the opening round in Australia, and his 74th of his career. He will be looking to extend that lead this weekend as he takes to the track in Barcelona.
Hamilton may have needed a huge stroke of luck to clinch his first victory of the season last time out in Baku - but it was all down to him and a superior vehicle in Barcelona.
Charles Leclerc of Sauber and Sergio Perez of Force India closed out the top 10.
The race got off to a chaotic start due to Romain Grosjean losing control.
That meant he returned to the track in fourth place. The Frenchman spun across the track, kept his foot down on the throttle and was collected by Hulkenberg and Gasly. Generally he likes spinning, but on the first lap is not a good time to do it with everyone there. Honourable mention for Verstappen for his drive with a damaged car.What happens next? In the end we weren't quick enough and our tyres didn't last as long as others. A one-two for the team.
Brendon Hartley of Toro Rosso did not make it to qualifying because the team was not able to fix his auto after a crash in the final minutes of Saturday's practice.