The opening week of the 2012 Tour de France has brought all the excitement we’d hoped for and the show down we’d expected.

Bradley Wiggins (Team Sky) and Cadel Evans (BMC Racing) have gone head-to-head on the three key stages of the race so far (at the prologue, and on the climbs of stage seven and eight).

Today’s ninth stage, a 41.5km individual time trial from Arc et Senans to Besançon, could be the most significant stage of the race to date, perhaps dictating how the race will unfold as it moves into the Alps in the week ahead.

Here are three obeservations from the first week to consider before today’s race of truth.

Evans is fearless

The transformation from cautious tactician to aggressor that followed Evans’ victory in the 2009 world road race championship has continued in fine style in the first week of this year’s Tour. The Australian made every attempt to gain time on Wiggins on the seventh and eighth stages, and is clearly not ready to concede his title in the face of Wiggins’ pre-Tour form. His attack on the entrance to La Planche des Belles Filles, and again at Porrentruy, showed he is more than happy to take the initiative, as he was last year in his Tour-winning ride.

Advantage Wiggins?

While Evans has been the aggressor, Wiggins has been able to respond. Much has been made of Team Sky’s formidable roster and discipline, but when the chips have gone down, the Londonder has been able to match Evans by his own efforts. When the attack of teammate Chris Froome at the summit of Las Planche des Belles Filles looked certain to succeed, Wiggins was content to keep tabs on Evans and follow the pair home. But when Evans’ assault the following day into Porrentruy threatened his position in yellow, Wiggins moved to the head of an elite chasing bunch to reel in the defending champion.

Time trial form

Wiggins finished 11 seconds ahead of Evans in the prologue time trial: a significant margin on a 6.4km course. Consider also that the Team Sky man rode conservatively on the first half of the course, pulling back six seconds on then-leader, Sylvain Chavanel, in the closing 3.2km. While the Londoner with his track pedigree would have been expected to hold the edge over Evans on a pan flat, prologue course, today’s rolling parcourse, at 41.5m significantly longer than the first timed effort, should produce a closer battle. The last time the pair met on an undulating time trial course, at the Criterium du Dauphine, Wiggins was the victor, finishing a convincing 1.43 ahead of Evans

Nibali is a serious contender

Team Sky rode every contender off their wheels on the climb to La Planche des Belles Filles on stage seven, with two exceptions. The first, Evans, we’ve discussed. The second was Vincenzo Nibali, who finished just five seconds down on the Australian and his shadow, Wiggins. The following day, on stage eight, the Liquigas-Cannondale leader split the two favourites to finish third, and is now just 16 seconds behind Wiggins on GC. Niabli is also a good time trialist. His biggest win of the season so far, victory at Tirenno-Adriatico, was completed with a top 10 finish in the race-closing time trial. He perhaps won’t contend for victory today (Tony Martin and Fabian Cancellara will start as favourites) or even trouble Wiggins or Evans too greatly, but a strong performance against the clock will set him up nicely for the second week of the Tour.