Omega Pharma Quick Step's Tony Martin won the Criterium Du Dauphine Individual Time Trial but it was not enough to prevent Rohan Dennis from taking over as race leader.
A fourth 32.5km stage from Villars-les-Dombes to Parc des Oiseaux, was seen as not only a battle between stage favourite Tony Martin, the World Time Trial Champion and Team Sky's Chris Froome, but a massive test on Europcar's David Vellieux and whether he could keep his leader's yellow jersey.
Czech Jan Barta of the NetApp-Endura team set the initial quickest time to beat with a time of 38:30, an average speed of 50.64kph.
However, it was a time that was soon in danger when Tony Martin went down the ramp. The German flew through the first time check at Rignieux-le-Franc, some 32 seconds quicker,
Whilst Martin was on the road, setting the fastest time vthrough the second checkpoint, Movistar's Jonathan Castroviejo set the new fastest finish time of 38.02.
Castroviejo's time on top of the leaderboard was brief as in came Martin with a time of 36:55. As good as this time was, it was not going to put Martin in the leader's jersey as Martin was 10.49 on Vellieux going into this fourth stage.
Martin admitted to letour.fr that it was not the best time trial he had ever ridden and said; "It was not my best time trial but it wasn’t a bad one either. "I’ve had stomach problems in the past few days. Fortunately, I’ve felt much better today but I was not at 100% of my capacities."
Garmin's Rohan Dennis, who was 1.57 down on Vellieux in the general classification, came in 37.42, forty seven seconds down Martin's time, putting himself in a good position if the race leader were to slip up.
Froome, with the number one on his back, came through the first checkpoint in third and was third at the second checkpoint, some 41 seconds down, whilst Alberto Contador was losing two minutes.
Froome finished in a time of 37.46 whilst for Contador, coming in 3.35 down on Tony Martin put a massive dent into his Dauphine ambitions.
Geraint Thomas finished in 38.35 for a provisional top ten place whilst back up the road, Vellieux was making good progress, some four seconds up on Dennis, who took the best young rider's jersey from Tony Gallopin, at the second checkpoint.
Second in the General Classification, the Green Jersey wearing Gianni Meersman came home in 92nd place and now all eyes were on David Vellieux.
The Canadian, lost time on the closing stages and came in with a time of 40.47 and that saw the leaders jersey move to the shoulders of Rohan Dennis, who is five seconds ahead of Chris Froome. Geraint Thomas is sixth.
Dennis said to letour.fr: "This a dream come true and I am stuck for words. "The aim was to go for the white jersey and I am so happy to be in yellow."
Time Trial Result
1 Tony Martin (Omega Pharma-QuickStep) 36:55
2 Rohan Dennis (Garmin-Sharp) 37.42
3 Christopher Froome (Sky) 37:46
4 Jonathan Castroviejo (Movistar) 38:02
5 Michel Kwiatkoswki (Omega Pharma-QuickStep) 38:08
Race Classifications after four stages
1 Rohan Dennis (Garmin-Sharp) 12:40:00
2 Chris Froome (Sky Procycling) +05
3 Michel Kwiatkoswki (Omega Pharma-QuickStep) +26
4 Edvald Boasson Hagen (Sky Procycling) +32
5 Richie Porte (Sky Procycling) +33