Red Bull duo Max Verstappen and Daniel Ricciardo admitted the team had work to do after being caught out by the deficit to Ferrari in dry conditions during Friday Practice at the Malaysian Grand Prix.

The two drivers dominated proceedings in the morning as a tropical downpour just before the start of Practice 1 led to a soggy start to the final Formula 1 weekend at Sepang, but once the weather had cleared, the situation changed dramatically with Sebastian Vettel putting the Scuderia on top, some eight-tenths clear of Ricciardo in third.

Verstappen was four-tenths further behind his teammate in fourth but had a sloppy lap on the Supersoft tyre to set his best time, including losing around half a second in just the final sector alone.

"We need to work hard on the car to improve," the Dutchman, who turns 20 on Saturday, said. "We need to see tonight if we can improve the balance of the car and then we can see if we can challenge the Ferraris. But they look very competitive."

His Australian colleague repeated Verstappen's comments and revealed the gap to Ferrari plus the lack of pace shown by Mercedes both went against his and Red Bull's predictions.

"I thought Mercedes would lead the pack and we would be a bit closer to Ferrari," he claimed.

Offering a little more insight into where in particular, the RB13 was struggling, the one-time race winner in 2017 added:"Short runs we need to improve the front grip and the long run we need to improve the rear.

"On the short runs it is simple things, we can add some front wing and be more aggressive on one lap with the tyre. On the long runs you have to look after the rears, with the temperatures so hot, just looking after that will be the key on Sunday."