It also set a record, one that Hamilton had previously shared with seven times champion Michael Schumacher, of 41 wins from pole position.
Hamilton crossed the line 20.5 seconds ahead of teammate Valtteri Bottas, giving a hint that Mercedes and Hamilton could be back to their dominant ways. With two podiums in the first four races, the Ferrari driver can still take some respite from his promising start to the campaign despite a disappointing day in Barcelona.
"In many ways, this is a weekend in which nothing went right", team principal Maurizio Arrivabene said. I had no idea what the pace would be like. "So I hope we can continue". I wouldn't say I had ideal synergy but close.
"That feeling that I'm going to sleep like a baby tonight, because I know I've done my job this weekend to the maximum and I didn't leave anything on the table, there's no better feeling".
"I'm really happy. I said I wanted to come and win in the way that I have won". That happiness and that uplift from inside that I have that feeling.
Ferrari - Lack of performance of flawed strategy?
The victory, in a race that stayed dry despite the threat of rain, was the Briton's second of the season, 64th of his career and third at the Circuit de Catalunya.
In the process he also extended his championship lead over Sebastian Vettel to 17 points.
Hamilton roared off his marks to retain his lead on the 200mph charge to the opening bend, while Vettel got the jump on Bottas after a gutsy move around the outside of the Mercedes.
"This is more like it", said a jubilant Hamilton as he crossed the line.
Andrew McCutchen makes emotional return to Pittsburgh
A few thoughts and observations about where the Pirates have been over the past few days and where they're headed ... San Francisco sends rookie Andrew Suarez to the bump for his 4th start of 2018 versus Pittsburgh.
Four children become orphans in Surabaya, Sidoarjo bombings
Three suicide blasts were committed by one family - a husband, wife and four children - against three churches in the town. It happened a day after a family of six carried out attacks on three churches there, killing 12 people and themselves.
Overwatch anniversary event date and new Junkrat skin revealed
And players that decide to purchase the 50 Loot Box Bundle will have a Legendary Anniversary Loot Box thrown in as a bonus too. In addition, deathmatch will include a new competitive mode that has placement matches, skill rating tiers, and leaderboards.
"Not every race feels as great as that one does". The degree of surprise increased further when they chose to send him out on the medium tyres instead of the softs.
"I think it's obviously a little bit early to say but I would like to hope that it could be part of a turning point. It is important these days to understand why and then you look back and understand what is missing in the preparation to the race". But inside the vehicle, we were going through the tyres too quick and therefore we were not able to stay out for another 23 laps. We were just not quick enough and even at the end I was not in a healthy shape with the tires even though mine were the freshest.
Hamilton, however, was in cruise control, as he made his one and only trouble-free stop on lap 25. On the mediums, his Ferrari could manage only half of the number of laps (24) as Bottas (47).
Vettel put their drop in form down to three things: speed, tyres - referring to the change in tread depth for this specific race - and reliability.
"I think you can only really take it one race at a time", he explained. They changed but they changed for everyone, so our ambition has to be we are better rather than worse off. "For sure, second is not ideal but for us today, it couldn't be better for us as a team".
The other issue for Ferrari was their unreliability. His 1:18.441 was more than three seconds faster than the previous record - a 1:21.670 - set by Kimi Raikkonen in 2008. If not off to Ferrari in 2019, Haas might be eager to have the young star in their vehicle instead of an underperforming Grosjean. In the Constructors' Championship, Ferrari trail Mercedes by 27 points.
Verstappen, whose season has been littered with collisions, also almost wrecked his race when he hit the rear of Canadian Lance Stroll's Williams and lost a front wing end-plate. Luckily for Verstappen, the damage was only to his front wing endplate and didn't limit his performance too much.
Daniel Ricciardo, meanwhile, had an anonymous race.
The American team showed excellent pace in pre-season testing in Barcelona and based on early-season results it would seem that low-fuel runs or some kind of testing trickery were not behind their headline times in testing. "It's a good feeling". If it's cold, like it has been in the coolest days here, it could be hard, but we definitely go there on a high note - and we definitely don't take for granted the fact that we still have a mountain to climb. Max Verstappen (Red Bull) +26.873, 4.
All three were out of the race in an instant to mark another embarrassing chapter for Grosjean after he crashed out under the safety vehicle last time out in Baku. Sergio Perez (Force India), 10. Carlos Sainz Jr (Renault), 8. Williams' Lance Stroll, who had more than a fair share of off-track excursions in the Free Practice sessions, finished approximately five seconds behind Leclerc in 11th place.