Championship leader Lewis Hamilton insists "nothing is out of reach" as he bids to defy the odds with victory at Sunday's Singapore Grand Prix.
Hamilton, who heads Sebastian Vettel by three points at the summit of the Formula One championship, was only third in practice at the Marina Bay circuit on Friday.
Daniel Ricciardo led the way from team-mate Max Verstappen, with Red Bull appearing in a class of one at this twisty and low-speed track.
But Hamilton has refused to give up hope of retaining the lead of the championship race in his quest to become the first British driver to win four world titles.
"We were obviously close with the field today and we have still got some improvements to make with the car," said Hamilton.
"Red Bull seem like they're very strong and they're thereabouts with Ferrari, so we've got some work to do, but nothing is out of reach."
Hamilton's title rival Sebastian Vettel was just 11th, but his result is somewhat skewed given that he failed to post a fast lap on the ultrasoft tyre, the quickest of the three compounds available.
Vettel went quicker than any other driver in the opening sector of what should have been his best lap, only to be blocked by the Sauber of Marcus Ericsson before abandoning his run.
To cap a scrappy evening, the four-time champion then thudded against a wall on the exit of turn 10, dislodging an advertising board, but escaped the incident without any significant damage to his car.
But with Vettel's team-mate Kimi Raikkonen only ninth in the standings, there will be some concern in the Ferrari camp on Friday night with the 3.2-mile street circuit expected to have played to their strengths.
This weekend's race could prove to be the only course of the remaining seven grands prix where Ferrari will hold the advantage over Hamilton and his Mercedes team.
Hamilton, who is in charge of the title race for the first time this season following his triumph at the Italian Grand Prix a fortnight ago, will feel somewhat relieved to have seen Vettel behind him with Mercedes braced for a difficult weekend.
The 32-year-old Englishman has won in Singapore on two occasions but has struggled in recent years, failing to get to the finish in 2015 before he ended a distant third to rival Nico Rosberg in last season's race.
But aside from the dominant Red Bulls, Hamilton was half-a-second clear of his fourth-placed Mercedes team-mate Valtteri Bottas.
Hamilton has been on pole position at both races since the summer break, and qualifying is crucial in Singapore with overtaking virtually impossible. Seven of the last nine pole-sitters have gone on to win.
Source: PA
