In his first professional season, Millar won the prologue of the Tour de l'Avenir and the competition for the best young rider in the Mi-Août Breton. He profited from his background in 10-mile time-trials in Britain to win the first stage of the 2000 Tour de France, a 16 km time-trial at Futuroscope. He held the yellow jersey as leader of the general classification for a few days. He failed to repeat his feat at Dunkirk in 2001 after puncturing in a bend and crashing. He finished fifth in the prologue in 2002 on a rolling course at Luxembourg. His attempt to win the prologue in central Paris in the centenary Tour of 2003 ended when his chain dropped off 500 m before the finish. He lost by 0.14 s to Brad McGee. Millar had ridden a bike without a front derailleur to save weight. He blamed his directeur sportif, Alain Bondue. "It wasn't a problem with my chainring; it was a problem with my team," he told journalists at the finish. He said Bondue had tried to save a few grams by removing the derailleur. Bondue said he had told Millar to use a front derailleur after other riders had similar problems. Bondue was demoted to logistics manager.