Omega Pharma Quick Step's Levi Leipheimer won the Individual Time Trial in the fourth stage of the Tour de San Luis on Thursday.
The American finished the 19.5km course, some 33 seconds quicker than Liquigas' Vincenzo Nibali (Liquigas-Cannondale) and a minute and one second quicker than Alberto Contador to take the race leaders jersey.
Leipheimer has a 23 second lead on Nibali going into Friday's fifth stage which is 160.6kms long and from La Toma to Merlo (Mirador del Sol)