Vettel and Ferrari will take heart from their respective records in Sepang - Vettel has won four races at the circuit - more than any other driver - and Ferrari boasts seven victories to Mercedes' one.
"The last race was a strong reminder that sport always has the power to surprise and defy all predictions", said Mercedes team boss Toto Wolff after the two Ferraris collided at Singapore. "I've been unwell this week and this is possibly the worst place to not feel 100%".
LewisHamilton once again made the difference for Mercedes as the Briton celebrated his 70th career Formula One pole in Malaysia on Saturday. Pierre Gasly as well as his teammate Carlos Sainz set impressive lap times to climb out of the drop zone as the checkered flag fell on the session.
Mercedes got both drivers back out after their trips into the gravel, but Bottas could only manage fifth, 1.459s adrift of Vettel.
The Red Bulls of Daniel Ricciardo and Max Verstappen came next and even the McLaren of Alonso, which has been poorly paced all season, was fifth in the afternoon after being third fastest in the wet first session. Before qualifying I was thinking of going back to the new package because Valtteri's and my times were very similar and Valtteri seemed really happy with it and so I didn't want to carry a penalty going into qualifying.
"We had such a hard day yesterday, hard to know where we stood", Hamilton said. "I've been struggling with the vehicle, so we have to review and try to understand where we have gone wrong with the balance".
Hamilton leads the F1 World Drivers' Championship by 28 points from Sebastian Vettel but could see that lead cut if they continue to lag behind the front-runners.
One of those title-defining memories came here a year ago as Lewis Hamilton suffered an engine failure while leading the race. This crash eliminated Sebastien Vettel, Kimi Raikkonen, and Max Verstappen.
"I think we have a lot of races left, I think we have a strong vehicle". He has been on a roll, winning four of the last five F1 races. "The next thing I knew, the tyre was not there anymore and I was just spinning and heading for the wall".
"When you get that close it's a disappointment", said Raikkonen. "But we go tomorrow".
Asked whether the new parts worked well, Alonso said: "They didn't today".
Mistakes on some level are unavoidable but the severity of Vettel sandwiching Red Bull's Max Verstappen in Singapore can not be underestimated in terms of the title.