After Dr Mario Theissen revealed that it was Nick Heidfeld's turnaround in form in recent weeks that ultimately saved his seat at BMW-Sauber in 2009, the experienced German seemed to suffer a relapse in qualifying for this weekend's Japanese Grand Prix, as he missed the Q2 cut for the second time this season.

Theissen admitted to having deliberated long and hard as to whether or not to hang onto Heidfeld - with BMW since the inception of the Bavarian manufacturer's official Formula 1 programme three years ago - in the wake of several poor performances in 2008.

The 31-year-old has, however, proven to be the third-highest scoring driver over the last three grands prix - and it was his improvement in qualifying in particular, his boss confessed, that had been critical to the retention of his drive.

"The decision was not easy as I had hoped for initially," Theissen acknowledged. "Initially we expected to take the decision in the summer break, but then Nick had quite a difficult [period], especially in qualifying. He wasn't able to get the perfect lap time together and so we decided to postpone the decision.

"At the same time, I gave him every support to overcome this weakness and so when we saw a significant improvement in the last two or three races, we could be confident that he was back on-form. He was back to his [old] performance, and that led us to the decision right after Singapore."

Lining up 16th on the starting grid in Fuji, however, is hardly the manner in which Heidfeld will have anticipated celebrating his contract extension, after a bold team strategy of remaining on Bridgestone's harder-spec rubber for both runs in Q1 badly backfired.

"Now we know it was the wrong decision to stay on the harder tyre compound for the second outing in Q1," the man from M?nchengladbach rued. "After my initial run on the first set of those tyres, I knew I could improve on the prime tyres, so we took the risk and put on another set.

"I actually did improve - I was about half a second quicker - but still it wasn't enough and I missed Q2 by one tenth of a second. Robert [Kubica] just made it.

"Of course from so far back on the grid it will be very difficult to do something in the race, but we have seen everything happen in Formula 1 and I shall never give up."

Indeed, after narrowly making it through to Q2 by less than two tenths of a second in 14th place - thereby avoiding the same fate as befell his team-mate - Kubica eventually succeeded in extracting sufficient pace from his F1.08 to seal a third row starting slot for Sunday and maintain his title hopes, for the time being at least.

"Yesterday we were struggling with low grip," the Pole reflected, "so the rain last night and this morning definitely didn't help us as it washed away the rubber. The balance of the car was fine, but it was just lacking grip.

"I tried everything I could and this was the best I could manage. Sixth is not bad under the circumstances."

Both BMW Motorsport Director Theissen and the Munich and Hinwil-based outfit's technical director Willy Rampf seemed to agree with Kubica's contention, whilst admitting that from virtually the back of the grid, Heidfeld's chances of notching up points have taken a considerable nosedive.

"Qualifying didn't go as we hoped it would," Theissen mused, with not a little understatement. "The main reason was we estimated incorrectly how the track conditions would improve, and their influence on the tyres in Q1. We sent both drivers out twice on the harder compound, while others were already changing to the softer tyres.

"The unexpected big difference between both compounds left us in the situation where Robert just made it into Q2 and Nick didn't. In the remaining qualifying sessions Robert put in the performance we were expecting and was sixth."

"The most difficult part of today was the first session of qualifying," agreed Rampf, "during which we planned to use the harder of the two tyre compounds. We wanted to have enough sets of the softer one for the remainder of qualifying and for the race.

"This decision cost Nick a place in Q2, [and] it will be difficult to score points from 16th. Robert's performance was strong and he managed to clinch sixth. This was what we realistically expected."