Britain's Chris Froome, the pre-race favourite, on Tuesday won the Tour of Romandie prologue, a 7.4km ride between Chable and Bruson, in a time of 13min 15secs.
The Sky team leader overtook Spain's Dani Moreno - the winner of last week's Fleche Wallonne - in a strong finish and crossed the line six seconds ahead of American rider Andrew Talansky.
Croatia's Robert Kiserlovski, was third, 13 seconds adrift of first place, while Australia's Richie Porte, a Sky team-mate of Froome, was fourth at 15secs.
"It was just seven kilometres but uphill, which is unusual for a prologue," Froome told Swiss television.
"I hadn't raced for a month, since the Criterium International (which Froome won) and I wasn't sure what kind of form I would be in.
"To win the prologue is a good sign and I hope to defend the leader's jersey for as long as possible this week but I know it will be difficult."
Wednesday's first stage is a 176.4km ride from St-Maurice to Renens, just outside Lausanne, with the five-stage race concluding on Sunday.
Froome will be hoping to not only win here but go on like the winners of the past two editions, Australian Cadel Evans and Froome's Sky team-mate Bradley Wiggins, and win the Tour de France in the same year.