Brawn GP are anticipating this weekend's Belgian Grand Prix at Spa-Francorchamps to be an acid test for whether the BGP 001's cold weather form has improved sufficiently over the summer break to enable the team to take the fight to chief title challengers Red Bull Racing around the high-speed Ardennes circuit.

In the first race back since the month-long hiatus, Rubens Barrichello put Brawn back on top of the pile for the first time in four starts with a commanding victory in the European Grand Prix in Valencia last weekend - but that was in baking temperatures and around a circuit that, by dint of its tight, twisty nature, was always likely to play far more to the strengths of the Mercedes-powered contender than its Renault-powered rival, for whom Mark Webber could do no better than ninth and Sebastian Vettel failed to see the chequered flag at all.

As the F1 circus heads to Spa this weekend - on paper Red Bull territory, due to its fats and flowing nature, and where the weather is likely to be unpredictable at best, with the only certainty being that of cooler climes - it will become clear whether Brawn has truly resolved the problems it suffered earlier in the campaign regarding getting heat into the tyres at lower temperatures. If not, the Brackley-based outfit could be in for a long weekend indeed.

"Our return to form in Valencia and the very well-deserved win for Rubens has given everyone at the team a timely boost as we head into the final part of the season," underlined team principal Ross Brawn. "Looking ahead to the race in Spa, this will be another challenge with a very different type of circuit and ambient weather conditions. Although we believe we now have a better understanding of our recent tyre issues, the lower track temperatures at Spa will be the proving ground for this.

"We will have another busy testing programme on Friday to validate the conclusions reached in Valencia, and will then build our weekend from there. Spa ranks as one of the great classic racing circuits, loved by drivers, engineers and fans, so we hope to put on a good show."

That much was corroborated by both Barrichello and world championship-leading team-mate Jenson Button, who produced a fourth off-colour showing in as many outings in Valencia to come home just seventh, more than half a minute shy of the Brazilian at the close. The British star knows he needs to get his title bid back on-track with a vengeance in Belgium - where he has previously finished on the podium, for BAR-Honda back in 2005 - if he is not to throw all his early-season hard work away when it matters most.

"Spa is one of my favourite circuits," enthused the 29-year-old, "and has a layout which gives everything you could want as a driver. It's one of the fastest and most challenging circuits in the world with hills, fast corners and long straights which combine to give you a real buzz to drive, just like Suzuka and Silverstone. It's also a very beautiful circuit with the forest setting, although the weather can be unpredictable! It can play a big part in the race weekend, even in the summer, so you have to be ready to react but that unpredictability is part of the thrill of racing at Spa.

"Eau Rouge is still a legendary corner, although it is usually easy flat for us in the dry. The feeling when you hit the bottom of the hill, touch the ground and shoot straight back up again is amazing. It's been a tough few races for me recently, but the car felt very good in Valencia and the pace was right up there when I was able to run in clear air during the race, so we're feeling positive and very much looking forward to the weekend."

"Valencia was a fantastic weekend and the memories will stay with me for a long time," added. "Winning again feels pretty good! I always knew that we had both the car and the pace to deliver a win this season and stayed positive. I've had a few days to relax and reflect now, but I can't wait to get back in the car again in Spa!

"For me, Spa is unquestionably on one of the best circuits in the world and I love racing there. The lap is really long and fast with some great corners, and it gives you a fantastic feeling in a Formula 1 car. Experience is a key factor, as you can pick up a lot of time if you get the car set-up just right and you have to be precise in your timing to make the most of the track time in practice and qualifying. We've picked up some momentum again now after the result in Valencia and know that we have to make the most of the next few races."