Mark Cavendish had the rare role of acting as a lead-out man for Tom Boonen on yesterday's third stage of the Tour de San Luis and he delivered the classics star perfectly on the uphill finishing straight. After being the one to open the sprint, Boonen faded and had to settle for 3rd but Cavendish is convinced that a win is looming around the corner for his Belgian teammate.

While most of the teams in the Tour de San Luis have lined up a team of climbers, Omega Pharma-Quick Step have done it differently. With Mark Cavendish, Tom Boonen and Alessandro Petacchi all in the original line-up, the Belgian team had travelled to Argentina with an eye on the many sprint finishes.

They took advantage of the parcours for the 175.8km stag 3 on Wednesday. The profile was undulating, with a slight uphill for the final three kilometers. Still, with only one categorized climb, it was quite possible the stage would be decided in a sprint.

There was a slight chance of chaos earlier in the stage, as temperatures of more than 40 degrees Celsius and high winds helped establish echelons after the race came back together with about 55km remaining in the stage. However, it was clear the stage was heading for the predicted bunch sprint as the peloton was back together inside the final 30km of racing.

In the final kilometer OPQS rider Mark Cavendish played the rare role of lead-out man, guiding Tom Boonen towards the line. Boonen jumped first among the riders in front, but was unable to hold his power as he finished 3rd behind Giacomo Nizzolo (Trek Factory Racing) and Francisco Ventoso (Movistar Team).

The team lost Alessandro Petacchi on day one due to gastroenteritis and the absence was clearly felt in yesterday's finale.

"Obviously we're a man down, we're without Petacchi," Cavendish said. "Guillaume [Van Keirsbulck] is also not really feeling well, so we're down to four of us. We had to use two guys near the finish to bring back a small group [with Pieter Weening and Daniel Diaz], and Stijn [Vandenbergh] also had a flat at 15km and he struggled to come back, so that left it up to me and Tom.

"We went for Tom today, I was leading Tom out so I tried to stay with the Lampre train and go at 300 and drop Tom off at 150 meters," he added. "But the wind was weird and the road curved to the left, so we had to leave it open. Nizzolo is just fast too though, so we can't be too bothered.

Despite Boonen fading near the end, Cavendish is convinced that his teammate will be back to his best after an injury-plagued season.

"Things went well," he said. "It was nice, me and Tom working together. Tom's form is going really good. It's possible for him to get a win really and it would be good for his head and he's really strong right now. You can see it when he's pulling. It's fine to do and we're working quite well."

Boonen was happy to get his chance after missing out on stage 1 where the peloton failed to catch the early break.

"We were planning on the first stage to give it a go and today we wanted to give it a go as well," he said. "I'm already in good condition, but these weather circumstances are really hard. It was the hottest day of my career. I was really suffering. Everybody was really suffering.

Boonen says that he was maybe a bit too eager to get success after his many woes in the past year.

"Going into the sprint I think everything went perfectly, but I think I wanted it too much," he said. "I think I went a bit too early. Cavendish gave me a good leadout and he still wasn't finished, but I saw the sign and I thought it was a headwind with a 3 to 4 percent uphill. I had the sensation that we weren't going fast enough so I just went. So when I came into the wind I felt I was going to lose by the last 30 meters. My legs just blew in the last five seconds.

"I'm already happy to be there, but if you're doing all those big efforts you want to do something more than 3rd place. But still it's a good sign. With four guys it's very hard for us, even with two fast guys everybody is always waiting for us. But we're doing our best despite that and think we did well considering the circumstances."

Boonen and Cavendish will take a back seat the next three days which offer two summit finishes and a time trial. Their final chance for success comes on the final day when the stage will again finish with an uphill sprint.