Sebastian Vettel's world championship hopes suffered another significant dent on Saturday as engine problems prevented the Ferrari driver from setting a time in qualifying for the Malaysian Grand Prix.
Vettel suffered a spectacular first-lap retirement in Singapore last time out, which saw him slip 28 points behind Mercedes' Lewis Hamilton in the standings.
And Hamilton would now appear to have a golden opportunity to extend his advantage, with Vettel set to start from the back of the grid at Sepang.
Ferrari's mechanics worked swiftly to complete what they described as a "precautional" engine change and get Vettel's car ready for Q1 after the German had suffered issues during Saturday's morning practice session.
However, Vettel soon reported further problems after taking to the track and it soon became clear he would be unable to complete a lap.
"On his preparation lap, he didn't feel the right amount of power coming into his engine, but the reason for that, we really have to investigate," a Ferrari spokesperson told Sky F1.
Vettel added: "It's part of motor racing. For sure, it's not ideal, not what you want, especially on a day when you feel you've got it in you [to claim pole position].
"We save some tyres, so there's obviously some positives, even though it's a pretty bad day.
"We need to see now what is the problem, but we managed to do the change successfully. They fixed it up so quickly and it's a shame that we couldn't get out and I couldn't get it where it belongs for them."
Ferrari will at least be able to change further engine components on Vettel's car without having to serve grid penalties, given he is already at the back of the grid.