Basel - Juan Martin del Potro edged closer to a spot at next month's ATP Finals as the fourth seed dispatched French qualifier Julien Benneteau 6-4, 6-4 to reach the Swiss Indoors quarter-finals on Thursday.
Del Potro won the Basel title in 2012 and 2013, beating seven-time champion Roger Federer in both of those finals.
The Argentinian is 14th in the standings with only two weeks remaining in the race to the eight-man season-ending tournament in London.
But with Andy Murray, Novak Djokovic and Stan Wawrinka not playing for the rest of the season due to injury, the South American's position is looking stronger and stronger.
Del Potro went into the Basel tournament 470 points adrift of Pablo Carreno Busta in the final qualifying place, with 500 points on offer in Basel before the final Masters 1000 event of the season next week in Paris.
He wasted little time in seeing off 93rd-ranked Benneteau, hammering 12 aces.
The 29-year-old saved the lone break point he faced while breaking his opponent twice to secure a 34th win of the season.
Del Potro has been on a good run of form in recent weeks, reaching the Shanghai Masters semi-finals and winning the Stockholm title last weekend.
Elsewhere in the second round at the St Jakobshalle, Hungarian Marton Fucsovics advanced to the last eight as Argentine Leonardo Mayer quit when trailing 3-0 in the first set.
Results from the ATP Swiss Indoors tournament in Basel on Thursday (x denotes seeding):
Juan Martn Del Potro (ARG x4) bt Julien Benneteau (FRA) 6-4, 6-4
Mrton Fucsovics (HUN) bt Leonardo Mayer (ARG) 3-0 - retired