Hamilton, who secured the 64th pole of his career to move to within one of his boyhood hero Ayrton Senna, finished just 0.051 seconds ahead of Vettel following a frenetic qualifying session at Barcelona's Circuit de Catalunya.
"Quite amusing at one point when one auto on one side of the garage was one or two mechanics, while the other one was completely crowded like bees hovering around the vehicle so I think great effort so big thanks". Mercedes had, after all, made some changes and upgrades ahead of the session.
"I don't know if the guys back at the factory get exhausted of hearing this, but they've done an incredible job".
"For most of the weekend we've had the edge on Ferrari but in Q3 they raised their game", he said. It wasn't the best lap of my weekend and also we had to go back to the old engine this morning.
The three-time champion Briton resisted a powerful late challenge in the final seconds of Q3 from championship-leading four-time champion Sebastian Vettel of Ferrari.
"Today was an important one for us with the new upgrade package on the auto", he said.
"Unbelievable, they did an engine change sub two hours".
"Stop the auto, stop the vehicle now", the German was told over the team radio.
Hamilton said: "The fans are awesome and I have been growing here over past 10 years, unbelievable job by team".
"It's always a morale boost when you come somewhere and it's not your home and you see support".More news: Trump suggests there may be 'tapes' of his private conversations with Comey
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"[Our] second run was really good up until that final chicane". I was happy yesterday and jumped straight in and feeling good. Everything is still wide open.
"It would have been nice to get them the pole, but hopefully we can do well tomorrow".
After the qualifying session, Hamilton was again all praises for the team. "Very tricky conditions today", said Raikkonen.
"Lewis did a great job: it was tricky to put the sectors together today, and I'm not sure any driver had a ideal lap, but he did two times good enough for pole position in Q3 and really deserved it".
Valtteri Bottas's Mercedes team broke the Friday night curfew to fix an electrical fault on his auto. There's no reason. He will stay in his team, he loves his team, everything is right.
(AP Photo/Emilio Morenatti). Mercedes driver Lewis Hamilton of Britain steers his auto during the third practice session for the Spanish Formula One Grand Prix at the Barcelona Catalunya racetrack in Montmelo, Spain, Saturday, May 13, 2017.
That Ferrari have matched Mercedes so closely is impressive - that Vettel even managed to take part in qualifying even more so.
"But it got the job done and that's what counts".
"We expected Valtteri to develop through every single race and step up his performance and he's shown that", Wolff said.