Sebastian Vettel says a lack of power is the reason why his Red Bull was so far behind the Mercedes drivers in Belgian Grand Prix qualifying.
The reigning Formula 1 world champion qualified third at Spa, but was a massive 2.126 seconds slower than polesitter Nico Rosberg, and 1.898s behind Lewis Hamilton.
Vettel put the gap purely down to his Renault engine being down on power compared to the Mercedes V6.
"The reason we're behind is fairly simple," said Vettel. "We know we are down on power.
"Mercedes can run a bit more wing level, they have more downforce and can still take that wing on the straight - it is the reason.
"Hopefully tomorrow we will be closer in race pace and closer than the last couple of races."
His team-mate Daniel Ricciardo, who qualified fifth, said Red Bull had run a dry set-up in qualifying because it could not afford to compromise straightline speed with extra downforce.
"Realistically we've set the car up for a dry race, so even though we're typically quite strong in the wet, we knew that our set-up would bring us down to the level of some guys around us," he said.
"The gap to Mercedes was pretty big. We thought we'd be able to close it up a bit in the wet. They were quick straight away, and it hurts a little bit. But it's alright.
"An explanation for now is that we've banked a little bit on a dry race tomorrow so we've set the car up for that. In a nutshell, we've taken downforce off for that.
"With the way our straightline speed is, we need a chance of fighting, moving forward or defending, and that's why we've gone the way we have."
Ricciardo reckoned a wild trip over the run-off at Blanchimont on his last lap cost him "a few tenths". He was 0.194s slower than his team-mate.
"It wasn't the quickest way around the corner, but when I went off I was just hoping to stay on some part of the track," said the winner of the last race in Hungary.
"There's a big puddle just after the AstroTurf, and I was hoping it wasn't just going to spit me into the wall."