Jenson Button has stressed the urgency of McLaren rediscovering their form if they are to have any chance of capturing the Formula One world titles this season.
McLaren went into the last grand prix in Hungary leading the constructors' championship, and with Button and team-mate Lewis Hamilton second and first respectively in the drivers' standings.
They emerged from it, however, losing the lead in both after their worst weekend of the year as Hamilton retired with a gearbox issue while Button could only finish eighth.
Worse for McLaren is that they realised how far they are behind in terms of performance compared to Red Bull Racing, while Ferrari have also now drawn level.
Much has been made of the legality of the front wing on both the Red Bull and Ferrari, with new regulations due to come into force ahead of next weekend's Belgian Grand Prix that may aid McLaren.
If so, Button knows McLaren have to take full advantage of the Spa circuit and the track at Monza for the following Italian Grand Prix before the five-race fly-away end to the campaign begins.
"We head into the Belgian Grand Prix knowing we have some catching up to do," said Button.
"We didn't have a particularly strong race in Hungary, and the whole team wants to get back to the front again as quickly as possible.
"While we're optimistic the bodywork rules clarification will close the gap among the top teams, and that Spa and Monza should suit our package better than the Hungaroring, it's still important we regain the momentum we'd reached earlier this season.
"While I don't think these two European races will be pivotal to the title fight, it will nonetheless be harder to introduce bigger upgrades to the car at the end-of-season fly-aways. So it's important for the whole team we score well in both events."
Button is particularly eager to do well in Spa following a first-lap crash last year at a time when he was coming under pressure in the title fight. The 30-year-old was forced to watch the remainder of the race from the Brawn GP garage after being hit by then Renault driver Romain Grosjean. "I love racing at Spa. It's one of the truly great circuits and a grand prix I'd love to win," added Button.