Jenson Button's Formula One championship rivals cannot afford to go on eschewing opportunities such as that handed to them on a plate at the Belgian Grand Prix.

That is the view of Button's fellow Brit, ex-F1 driver and current BBC television pundit Martin Brundle, who believes that the points leader again got off lightly after crashing out on the opening lap at Spa-Francorchamps.

While the accident was not Button's fault - he was tagged by Renault rookie Romain Grosjean after making a better than expected start from 14th on the grid - it opened the door to rivals Rubens Barrichello, Mark Webber and Sebastian Vettel, although only the German really made the most of it. From Button's perspective, however, that was the perfect result, as the man from Heppenheim had slipped to fourth overall after two non-finishes and could only close the gap by six points after trailing in third behind Kimi Raikkonen and Giancarlo Fisichella.

That was not the outcome many were predicting for either Red Bull entry, both before the weekend and even after Friday practice, but Vettel's podium was the height of the team's achievement after Mark Webber again failed to trouble the scorers, this time courtesy of a drive-thru' penalty for an unsafe pit release that almost took BMW Sauber's Nick Heidfeld into the wall.

"I had a good first lap and laid the right foundations to get some good points today," Webber sighed, "but, after [the penalty], it was a case of damage limitation. I tried to get back into the points and, when we had free air - which was not often - we had good pace, but it wasn't enough. It's very frustrating not to take any points away, especially as I thought I deserved them from that drive, but the drive-thru' wrecked that. No one's interested in excuses though - that's how it is."

Brundle, meanwhile, confirmed Webber's dejection, and reported that the entire Red Bull team had been perplexed by the sudden loss of pace compared to others on the grid.

"When I spoke to Mark on Saturday morning, his mind was already on the race and working out how to outfox the KERS runners up the hill - as far as he was concerned, he was already at or near the front of the grid," the Briton wrote in his regular BBC column, "However, even an hour before the race, the team was still wondering where the relative pace they had shown on Friday had disappeared to. And they were not alone in that; similar discussions were going on at Brawn and McLaren."

With both Webber and Vettel now having suffered back-to-back non-scores in the past three races, Button appears to have got off extremely lightly, especially as Valencia winner - and Brawn team-mate - Barrichello, had his Spa race ruined at the very start.

"Red Bull don't have one driver consistently collecting the big points and that compounds their problems," Brundle continued, "If [Webber] hadn't served a drive-through penalty, he would have had a solid result, [while] Vettel finished third having had some early dramas and a very poor first lap. In the end, he was just 3.8secs away from winner Raikkonen and that just shows how well the Red Bulls should have done.

"Barrichello started fourth on the grid, but his engine revs bogged down and anti-stall system kicked in for the second time this season. He did well to stay out of trouble, but only grabbed two points for seventh place. Once the team recognised the problems off the start, they were quite smart in switching him to a regular two-stop strategy and he drove a good race, but it could have been so much better for him and major pain for Button."

Indeed, Barrichello remains Button's closest challenger in the title race, but closed only to within 16 points of the Briton, and now needs to out-score him by more than three points a round if he is snatch the title.

"In this bizarre championship battle, Button is giving everybody an open goal to aim at and they all keep missing," Brundle concluded, "He is now coming off five dismal races by his 2009 standards.

"It was hardly his fault that he crashed in Spa. If you are being Mr Sensible, thinking about your race and protecting your championship lead, and then a gung-ho new boy runs you off the road what can you do? However, Button shouldn't have been so far back on the grid in the first place. He made a second consecutive and crucial mistake in qualifying to find himself in the danger zone for the race.

"But the bottom line is [that] he has taken eleven points from five GPs and is still 16 points clear at the top of the championship. He has the points, the car, the silky smooth speed, and all the ingredients to be the 2009 world champ, but does he have the head? I sense he may rebound from Spa."