"We had such a hard day yesterday, it was hard to know where we stood", Hamilton said. So a surprise to be up here but I'm very grateful.
And non-executive chairman Niki Lauda added: "This again was a Lewis lap".
"But I know I made the most out of it".
At the time of the switch Vettel said he had moved to the finger hole clutch arrangement (below) because it said it gave him a better feel as he moved away at the lights. "Maybe we shouldn't underestimate the driving factor".
Meanwhile, Hamilton's team mate Valtteri Bottas finished in fifth position. While Bottas continued to use the new kit, Hamilton reverted to the parts he had used previously this season.
"Today we arrived and the vehicle was much better but still it looked like Ferrari was a little bit ahead, so some big calls to make ahead of qualifying".
Bottas was only fifth, nearly seven tenths adrift of Hamilton.
With the initial runs over, the order was Hamilton, Raikkonen, Vettel, Verstappen, Bottas, Ricciardo, Perez and Ocon.
"Not blessed", was Wolff's unique take on the session when quizzed by Sky F1.
"Obviously I lost power, just after sector one, and then limped back", said Vettel. His demeanour mirrored that of Hamilton after this race past year - a sense of acceptance of the position and a determination to do everything within his power to continue the fight. "The key area we are going to need to focus on tonight will be getting the maximum out of the tyres over one lap". "Tomorrow is a long race and it will be tough for tires".
With Vettel at the back of the field, Raikkonen will lead Ferrari's charge after missing out on pole by a mere 0.045 seconds.
"It's a bit more painful when you get that close", the softly spoken Finnish driver said.
The morning practice was shortened by rain and in the afternoon, when the cars could run on slick tyres, the session ended 20 minutes early when Romain Grosjean hit a loose drain cover, which should have been welded down securely.
Vettel was spotted in the Ferrari cockpit at Sepang on Thursday afternoon working intensely with the mechanics on the steering wheel arrangement.
Mechanics began working on the vehicle and, although it appeared at one point he was going to head back out on track to try to get through the session, in the end the team ran out of time.