Basel - Marin Cilic stayed in the chase for a spot at the ATP World Tour Finals on Thursday when he reached the quarter-finals of the Swiss Indoors with a 6-0, 7-6 (7/4) win over Pablo Carreno Busta.
After defeating the winner of the Moscow title last week, fourth seed Cilic will next line up against a second Spaniard when he plays Marcel Granollers, a 6-3, 6-1 winner over eighth seed Jack Sock.
Cilic, whose Croatia will play at home next month in the Davis Cup final against Argentina, is concentrating on both goals as the 2016 season wraps up.
The 2014 US Open champion currently stands two spots away from a possible place in the eight-man field for the World Tour Finals in London.
He is chasing Belgian David Goffin, who was taking on Juan Martin Del Potro in the second round later on Thursday at the St Jakobshalle.
Cilic won the last six points of his match against Carreno Busta after trailing 0-4 in the second-set tiebreaker.
He delivered nine aces and 21 winners in a tie lasting just under 90 minutes.
In another second-round contest, Gilles Muller of Luxembourg beat Germany's Florian Mayer 6-3, 6-2.
Top seed Stan Wawrinka was bidding for his first Basel quarter-final since 2011 in a later match against qualifier Donald Young.
Results on the fourth day of the Swiss ATP Indoors on Thursday (x denotes seeded player):
Marin Cilic (CRO x4) bt Pablo Carreno Busta (ESP) 6-0, 7-6 (7/4)
Marcel Granollers (ESP) bt Jack Sock (USA x8) 6-3, 6-1
Gilles Muller (LUX) bt Florian Mayer (GER) 6-3, 6-2