But it was a win his team identified as crucial to his self-belief and confidence for his title defence. It was clear, then, that they were the team and driver to beat. Hamilton led Vettel by 12 seconds and stayed out as the German pitted, comparatively slowly, for fresh medium tyres and rejoined fourth.
Mercedes' auto is fast and both Hamilton and Bottas are blistering quick, but in the race Ferrari might just prove to be quicker.
Vettel said he was "not entirely happy" but already expected Mercedes to be strong. "But we still have improvements to make and performance to add to the vehicle". This is hard to cope with and in the following races we struggled and all that adds up and was in all our minds. "This is a good way to start the weekend".
"Monaco could be a very different story", added Wolff. Logic would tell you that the faster tyre is the better option, but Ferrari, like Red Bull, believed that the Soft tyre would give them better performance.
It should also be a good chance for Red Bull to bounce back after last race's disaster.
Hamilton echoed the optimism coming from Wolff.
Hamilton said: "The vehicle and myself, I felt that synergy that I hadn't been feeling all year".
"Overall we were a little bit quicker [than Verstappen] but as the laps went on, we just didn't have enough pace". The changes should make cars go a second and a half slower, however.
He continued: "I'm almost in the groove".
Hamilton said the Pirelli tyres were partly responsible.
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Results from the Spanish Grand Prix are below.
"We had such a good auto, the team was so reactive today with the strategy".
But Ferrari brought him in for a second pitstop when the virtual safety auto appeared just past half-distance, dropping Vettel from second to fourth.
Mercedes held firm to their one-stop plan. Following a safety vehicle appearance, Hamilton got the whole shot on the restart and rabbited away.
Wolff sympathised with his rivals at the Scuderia.
"Everything we bring to the track is delivering the expectations and the lap times we were expecting from them", Alonso said. "Ferrari did the opposite".
"I got a decent lap", said Bottas, who was leading in Azerbaijan when a tire blew near the end of the race.
Lewis Hamilton celebrates victory in Barcelona. He has won more thrilling races in the past and will do so in the future. The speed is there and the driveability is much better than Mercedes' vehicle. Sensitive nerves no longer jangling, Hamilton leaves Barcelona with the assured calm he has been looking for since reeling from that shell-shocked second in Melbourne.
Esteban Ocon was another that failed to finish.
Mexican Sergio Perez of Pressure India made a late overtaking transfer on Sauber's Charles Leclerc for ninth, but it surely had been one other spectacular drive by the younger Monagesque. It capped off a disappointing afternoon for Ferrari, who saw Kimi Raikkonen retire after suffering a loss of power with a brand new engine which had been fitted to his vehicle on Saturday morning.