Del Potro has won four titles in 2008
Juan Martin del Potro boosted his Masters Cup hopes with victory over Mario Ancic at the Paris Masters.
The Argentine won 6-0 6-4 to reach the second round, with Briton Andy Murray a potential quarter-final opponent.
Del Potro, 20, is currently seventh in the race to make the eight-man field for next month's Masters Cup.
Novak Djokovic reached the third round when Dmitry Tursunov withdrew from their match because of a shoulder injury, when he was trailing 6-2 4-3.
Djokovic, whose next opponent will be Radek Stepanek, walked onto court wearing a Zorro mask and admitted: "I am still trying to find my top form. Lately I've been struggling on the court.
"But still I'm fighting. I know that I have to fight for every point and just find my best shape."
Murray, who is going for a third successive Masters Series title, opens his campaign against American Sam Querrey on Wednesday.
Djokovic walked onto court wearing a Zorro mask
Earlier on Tuesday, France's Gael Monfils made the third round with a 6-4 6-4 win over Argentine Juan Monaco.
World number one Rafael Nadal will face Florent Serra in the second round after the Frenchman beat Guillermo Canas, and there were first-round wins for Radek Stepanek, Ivan Ljubicic, Philipp Kohlschreiber, Robin Soderling and Andy Roddick.