Lack of grip cost us dearly - McLaren's Jenson Button
McLaren's world champion Jenson Button said his team hit the lowest point of their season in Hungary as Red Bull and Ferrari left them firmly in the shade.
Red Bull's Mark Webber won the race, taking the drivers' championship lead from Lewis Hamilton, who retired, while McLaren team-mate Button was eighth.
"It's the toughest day we've had this year," said 30-year-old Button.
"But this McLaren team has had some dark days in the past and bounced back from those, so I'm pretty confident."
McLaren - who also lost the lead at the top of the constructors' championship to Red Bull after a thrilling race at the Hungaroring in which Ferrari finished second and fourth - never really looked likely to threaten the podium after modest showings in practice and qualifying.
It's mentally draining fighting for position
McLaren now face a two-week mid-season summer break during which Formula 1 teams cannot do any work - but as soon as they are able to, the British-based team are keen to bring about a raft of improvements to a car which has not delivered recently.
"We'll be doing all we can to make sure the car works [at the next race] in Spa," Button, who started the race in 11th, told the BBC. "And I'm pretty sure it will happen.
"In qualifying I really struggled to get a balance, didn't get into the top 10 - and that made it difficult.
"I didn't have the pace in the race. I just didn't have any grip, locking front, locking rears.
"It's mentally draining fighting for position, but it's pretty crazy how close the championship is at the moment.
McLaren remain focused after disappointing weekend
"The Red Bulls are on top now, and in the last couple of races they've had such a performance advantage. They have jumped ahead of us, and we have to find our pace."
McLaren team boss Martin Whitmarsh echoed Button's words after a race in which Red Bull's pole-sitter Sebastian Vettel finished third following a drive-through penalty, leaving the title race wide open.
"We now need to make some developments improvements to take the car forward and have a reasonable track record in that," stated Whitmarsh.
"It was always going to be a race until the end of the season. Red Bull are prone to making mistakes but we must not throw away potential podiums, as we may have done today."
Hamilton retired with a gearbox problem on lap 24 while running well in fourth position.
"That's racing. We just have to work very hard to catch up," the 25-year-old reflected.
"We've lost a lot of points today. That's the second time this year. Hopefully we can work very hard so in the next few races we don't have any problems. It doesn't help for sure, but there's nothing you can do. We always do a phenomenal job normally.
"It's a shame to have the fault here at this point of the year, but that's life. This is motor sport and when you're pushing the cars to the limit these things can happen. We just have to go away and try and learn from this."
The Belgian Grand Prix takes place on Sunday 29 August.
Highlights - Hungarian Grand Prix