Senna's seat under threat at Williams

A dramatic weekend for Williams that saw the highs of claiming their first Grand Prix victory in eight years followed by the drama of the pit lane fire have ended up transforming the outlook for the team.

But it's looking increasingly likely that Bruno Senna won't be a part of those plans in 2013, especially after the weekend's stunning events coming on top of the news of Williams' latest Finnish sponsors coming on board.

Senna's seat was already under threat coming into the Spanish Grand Prix in Barcelona, after failing to make it through Q2 in any of the first four races of 2012. He did deliver the first championship points of the year for the team with sixth place in Malaysia and seventh in China, but struggled and ended up retiring at the end of the Bahrain Grand Prix with handling issues.

Friday practice at Barcelona saw him comprehensively outperformed by the team's test and reserve driver Valtteri Bottas, who was up in fifth place in the timings for Friday's FP1 session in Senna's car; Senna himself was only 18th fastest in the afternoon session, in what amounted to a direct comparison of the two drivers to the detriment of the Brazilian.

Bottas said that he had "really enjoyed" his session and stressed that this was the first time he hadn't been learning a circuit from scratch: "This was the first track of the season that I already know so it was nice for me to be able to focus purely on the driving from the start."

Bottas has already been handed the FP1 outing for 15 of the 20 Grand Prix weekends, limiting Senna's opportunity to familiarise himself with the track and putting him on the back foot for the race itself. But then in the run-up to Barcelona came news of Williams' latest sponsorship signings.

One deal is with Finnish business enterprise Wihuri, a longtime sponsor of Bottas since 2006. The second is with a Finnish welding manufacturer called Kempii - which has sponsored Bottas since 2008.

It's not exactly a master feat of detection to join these dots and conclude that Bottas' signing for 2013 is a done deal, even if it has not yet been formally announced or confirmed by the Grove-based team.

While it's long been known that Williams has been grooming Bottas to take a race seat with them next season - Bottas is even managed by Williams investor Toto Wolff - it was still unclear who would be the odd man out. Senna had been seen as at least a match for Pastor Maldonado, who brought with him a lot of sponsorship money from Venezuela but was widely dismissed as being 'just a pay driver'.

The Spanish Grand Prix changed all of that, and with Maldonado not just a Grand Prix winner with a stunning, perfect drive making him something of a fairytale success for the team, not to mention a national hero back home, the Venezuelan is suddenly too big a star for Williams to lose anytime soon.

The pressure on Senna showed on Saturday when he found himself pushing too hard in the first round of qualifying and spinning off into the gravel, meaning he started in 17th position on the grid while Maldonado made it onto pole.

And while Maldonado went on to win the race at the Circuit de Catalunya, Senna's weekend ended as early as lap 12 when he was rear-ended by Michael Schumacher. Schumacher got a five-place grid penalty in Monaco for causing the accident, but even so getting blasted on live TV by a multiple former world champion didn't exactly do Senna's standing any favours.

"It has been a disappointing weekend for me on the whole," admitted Senna after the race. "Schumacher got a big DRS boost coming down the straight and went into the back of me. These weekends with lots of bad luck happen sometimes."

They might, but it couldn't have been a worse combination of factors and timing for him. All of this points to Senna as being the driver out in the cold at the end of 2012 when his one year contract with the team expires, leaving Bottas to take a full time seat and Maldonado as the proven race-winning team leader.

The story of Williams' weekend shows just how much can happen and how stars can rise and fall in the course of four days.