MILAN — Lance Armstrong will compete in his first race in Europe since winning his seventh Tour de France in 2005 when he lines up in Saturday's Milan-San Remo classic.

After three-and-a-half years in retirement, Armstrong returned at the start of this season, finishing 29th in the Tour Down Under in Australia and seventh in the Tour of California.

Before retiring, Armstrong raced the Milan-San Remo six times and never won. He likely won't want to risk injury in a mass sprint and isn't in top form yet.

Italian favorites Alessandro Petacchi and Daniele Bennati will face challenges from the likes of Tom Boonen and Thor Hushovd.

On Friday morning, Armstrong rode a key climb for the Milan-San Remo, the 4.16-mile ascent to Le Manie, located about 62 miles from the finish. The climb was added to the race for the first time last year, and it eliminated several sprinters from contention.

"Just rode the Le Manie climb for tomorrow's MSR," Armstrong wrote on his Twitter feed. "Climb's not bad but the turn off the coast??? Wow. 200 guys trying to go where 4 can fit."

This year's race — the 100th anniversary edition — measures 185 miles, making it the longest of the single-day classics. After seven hours, the race is usually decided in a sprint, and that's where Petacchi and Bennati excel.

Petacchi won in 2005 and finished second in 2006 before injuring his knee and getting hit with a doping ban for excessive use of an asthma drug.

Signaling a return to form for the 35-year-old, Petacchi beat Bennati in the second stage of the Tirreno-Adriatico last week.

"I respect everyone but fear nobody," Petacchi said. "We're going to have to be careful to watch those riders who want to anticipate the group sprint."

That was exactly how Fabian Cancellara won last year, by turning on the motor that led to an Olympic time trial gold and breaking away from the pack 1.2 miles from the finish.

Struggling with his form, Cancellara has decided not to defend his title.

The 28-year-old Bennati is considered the next in Italy's long line of great sprinters after Petacchi and Mario Cipollini, but he still doesn't have any major victories.

Bennati can count on strong support in the Liquigas team, with former Giro d'Italia winner Ivan Basso, Franco Pellizotti and Vincenzo Nibali leading him up the race's two key climbs — the Cipressa and Poggio — shortly before the finish.

"We're counting on escorting him to the finish with several riders, protecting him from late attacks," Liquigas director Roberto Amadio said of Bennati. "Then it will be up to Murilo Fischer and Fabio Sabatini to set him up on the final straight."

Petacchi will also be helped by a former Giro winner in Danilo Di Luca.

"Alessandro is riding very strongly. The Tirreno-Adriatico confirmed that," Di Luca said. "We're good friends and therefore helping him won't be a problem."

Belgian standout Boonen finished fourth in 2006 and third in 2007. He and Frenchman Sylvain Chavanel form a strong 1-2 punch for the Quickstep team.

Chavenel won a stage in the Paris-Nice race last week and wore the leader's jersey for three days.

Quickstep also features Australian Allan Davis, the current leader of the UCI rankings.

The new Katusha squad also has a two-pronged attack in Filippo Pozzato, the 2006 winner and last year's runner-up, and Australian sprint specialist Robbie McEwen.

Hushovd finished third in 2005 and has been testing out the finish with Armstrong for the past week.

Mark Cavendish of Britain is perhaps the best pure sprinter at the moment, but he has acknowledged that he will suffer too much on the climbs to contest for victory.

Other possible contenders include Paris-Nice winner Luis Leon Sanchez of Spain and Tirreno-Adriatico champion Michele Scarponi.