PENAFIEL (Spain) (AFP) Italys Vincenzo Nibali reclaimed the race leaders red jersey from Spaniard Joaquin Rodriguez after the crucial 17th stage time trial of the Tour of Spain on Wednesday. Slovakian Peter Velits stunned a host of big favourites, including Swiss Olympic time trial champion Fabian Cancellera, to take the stage victory after the flat 46 km ride around Penafiel in north-central Spain. The HTC-Columbia rider covered the course in 52min 43 secs to finish 12secs faster than Russias two-time Tour of Spain winner Denis Menchov and 37secs better than Cancellara in third. Liquigas all-rounder Nibali, fighting to regain the lead he lost to Rodriguez on Monday, had a disastrous start suffering a flat tire and losing at least 30secs due to a rather delayed change. But the Sicilian recomposed himself to finish 15th, just 1:54 slower than Velits and a massive four minutes faster than Katushas climbing specialist Rodriguez. Nibali now holds a 39sec overall lead over Spains Ezequiel Mosquera of the Xacobeo team, and with Rodriguez dropping to fifth at 3:45 adrift Spanish eyes will now be on climbing specialist Mosquera. The title decider is fully expected to come on Saturdays mountainous penultimate stage, a 168.8km ride which ends on the summit of the Bola del Mundo in the Guadarrama mountain range northwest of Madrid. Im happy, on Saturday well see who wins, said Nibali. I rode very strongly in this time trial, from now on my great rival is Ezequiel Mosquera. The Bola del Mundo stage is very difficult, very hard. Mosquera said he had always dreamed of winning the Vuelta, but Nibali has shown that hes a solid leader, we have all attacked him and the guy held up, and didnt lose his nerve. Rodriguez, whose comparatively small stature means he is always at an advantage in time trials, admitted he failed completely during the stage. I tried to give everything, but when you cant do it, you cant do it. Only a miracle would have saved me, he said.