Jenson Button has described McLaren's lack of pace in qualifying for the Belgian Grand Prix as a "massive surprise".
The 2009 world champion was a lowly 17th at Spa-Francorchamps and was one second behind the next car, Sauber's Felipe Nasr.
Fernando Alonso qualified 18th - a further half-a-second down on Button - and both drivers will be demoted to the back of the pack after a combined and unprecedented 105-place grid penalty following a raft of changes to their new Honda engine.
"I think we knew this weekend was going to be difficult but after practice I thought we were sort of half a second behind the cars in front, which is already a massive margin," Button said.
"When I completed the lap, I thought it was good and then I was told P17 and a second behind the car in front, which was a massive surprise. I didn't expect to be that far off.
"I don't feel like I could have done any better and that's all I can take from it really."
McLaren secured their first double points finish of the season at the last race in Hungary after Alonso crossed the line in fifth and Button placed ninth.
The ailing team have desperately struggled here in Spa - a track which runs in excess of four miles and relies heavily on power - and were faster than only the Manor pair of Will Stevens and Roberto Merhi on Saturday.
"It's not going to be easy to make up any ground," said Button. "The only people we are going to be able to overtake are the Manors, and the rest will be gone.
"It will be Fernando and myself battling it out, and I don't think we'll be seeing another car until they lap us."
But Alonso, the double world champion who re-joined McLaren from Ferrari, remained in jovial mood. "We should get a cake", he said in response to their record grid penalty.
Source: PA
