Leipheimer pushes Contador off San Luis podium

The stage win was the Belgian team's third of the seven-stage Argentinian tour, with sprinter Francesco Chicchi recording two earlier victories.

Leipheimer finished the race against the clock 23 seconds ahead of Italian Vincenzo Nibali (Liquigas-Cannondale). Stefan Schumacher of Christina Watches-Ofone was third, a further 15 seconds behind.

Pre-stage race leader Alberto Contador finished sixth, which dropped the three-time Tour de France winner to fourth place overall at 57 seconds.

Leipheimer leads the general classification, 53 seconds ahead of Germany's Schumacher, with Nibali 55 seconds off the lead in third.

“I really wanted to do well today,” said Leipheimer. “After yesterday’s stage and the recon we pulled on the route this morning I knew I could compete. I really wanted to thank the team for the faith they placed in me and the guys who are here for the fantastic job they’re doing day in and day out.

"I think I did the best I could. We worked well and we’re enjoying the benefits. The time trial was anything but simple. The wind was also an important factor. We had to stay concentrated, especially in the final four kilometres, which were absolutely gruelling."

Of the key riders, Nibali was the first to post a stage-leading time but Leipheimer, a noted rider against the clock, proved his early season fitness with a dominating response. Contador was last out of the starting gate but was unable to keep pace with the diminutive American.

”Leipheimer was the natural favorite to take the win today and he a very good job on the time trial," Saxo Bank sporting director Philippe Mauduit said.

"As I mentioned before, Alberto is not in peak shape and that influences his performance today. And he doesn't have to peak at this moment. With yesterday's big win, he showed his great class by winning a mountain stage after six months' break from racing and that's more than we could have hoped for."

The race continues with the 160.6km fifth stage starting at La Toma and concluding with a mountain finish at Mirador del Sol.

Stage 4: 19.5km ITT, San Luis
1 Levi Leipheimer (USA) Omega Pharma-QuickStep 22min 33sec
2 Vincenzo Nibali (Ita) Liquigas-Cannondale 00:23
3 Stefan Schumacher (Ger) Christina Watches-Ofone 00:38
4 Sylvain Chavanel (Fra) Omega Pharma-QuickStep 00:39
5 Magno Prado (Bra) Funvic-Pidamonhangab 00:44
6 Alberto Contador (Spa) Saxo Bank 01:01
7 Matias Medici (Arg) Argentina 01:03
8 Cristian Martinez (Arg) San Luis Somos Todos 01:06
9 Luis Mansilla (Chi) Chile 01:11
10 Jorge Giacinti (Arg) San Luis Somos Todos

General classification
1 Levi Leipheimer (USA) Omega Pharma-QuickStep 13hr 07min 52sec
2 Stefan Schumacher (Ger) Christina Watches-Ofone 0:00:53
3 Vincenzo Nibali (Ita) Liquigas-Cannondale 0:00:55
4 Alberto Contador (Spa) Saxo Bank 0:00:57
5 Sylvain Chavanel (Fra) Omega Pharma-QuickStep 0:01:20
6 Daniel Diaz (Arg) San Luis Somos Todos 0:01:36
7 Luis Mansilla (Chi) Chile 0:01:43
8 Jose Serpa Perez (Col) Androni Giocattoli 0:01:49
9 Magno Prado (Bra) Funvic-Pidamonhangab
10 Andrey Amador (CRc) Movistar 0:02:51