Daniel Ricciardo can't explain why Red Bull has improved in Bahrain

Red Bull qualified more than one second adrift of pole position in Australia and China, but at the third round of the season Ricciardo was just 0.7s behind polesitter Valtteri Bottas's Mercedes.

With the team having looked strong through free practice as well, Ricciardo said Red Bull didn't yet have answers about why it appears to have made gains relative to Mercedes and Ferrari.

"To be honest, for me now, I don't understand it," said Ricciardo.

"In a way it's encouraging that the speed is there, and maybe if we really understand it we will find even more.

"The laptime we've got this weekend feels like it is for free because we don't feel it's something fundamental yet.

"It's a bit, 'OK, now we're a bit closer' and if we actually put something on the car that we know if definitely going to be better then maybe it can put us closer than we thought."

Ricciardo said the sudden upturn in performance could allow Red Bull to adjust its goals for the upcoming races.

"It's weird because we came here and it's a week since the last race and there's not much that we could have put on the car," he added.

"There's little bits here and there but there's nothing on the car that meant we should be half a second closer to pole.

"Last week I was pretty pessimistic about us being on the podium in equal conditions, but maybe it will be sooner than we think."

Ricciardo believes it will be hard to move forward to trouble the Mercedes drivers and Sebastian Vettel, while he is unsure of his true pace relative to Kimi Raikkonen.

"I don't expect to be in their fight tomorrow," he said of the leaders.

"If Seb does a good race he will probably be out of reach, but we've got one Ferrari behind so we'll try and keep that.

"I look at Kimi's lap and say he probably left something on the table - then I look at Seb and he's only three tenths in front of me, so that's the more encouraging thing.

"I expected a bigger gap to Seb, so that's cool."

Team-mate Max Verstappen, who felt his final lap was "ruined" by Felipe Massa in Q3, believes Red Bull is gaining more knowledge about its 2017 car.

"It's just little things because it's a really new car this year," he said.

"We had to understand it maybe a bit more than Mercedes and Ferrari from the first few races but it seems to work a bit better now.

"We worked on the car and every little detail to optimise it and it seemed to improve."