Argentine tennis ace Juan Martin del Potro and top-seeded swiss ace Stan Wawrinka moved into the Swiss Indoors quarterfinals on Thursday.
Del Potro beat fifth-seeded David Goffin of Belgium 7-5,6-3, while Wawrinka had 16 aces as he beat American player Donald Young 7-6 (4), 6-7 (3), 6-4.
Both players held their serve in the first set and dropped it once in the second. Wawrinka, the US Open champion,took the only chance he got on Young's serve in the deciding set.
Del Potro, who won the Stockholm indoor title Sunday,extended his winning streak to seven matches six againstplayers higher in the standings than the 42nd-ranked Argentine player.
Goffin, who beat Del Potro at the Shanghai Masters twoweeks ago, struggled with his second serves and was brokenonce in each set. Del Potro won back-to-back titles at Basel in 2012 and 2013 but missed the last two editions due to left wristinjuries that dropped his ranking sharply. The 28-year-oldwill play No. 5 Kei Nishikori of Japan on Friday.
Wawrinka, who was also taken to three sets in the first round, next faces Mischa Zverev of Germany, who beat GuidoPella of Argentina 6-4, 6-2. He broke Pella's serve threetimes and saved both chances on his own serve.
Earlier, fourth-seeded Marin Cilic the 2014 US Openchampion had 10 aces in a 6-0, 7-6 (4) win over Pablo CarrenoBusta. Cilic lost only five points in the first set againstthe 32nd-ranked Spaniard. The second set went with serve, andCilic trailed in the tiebreaker before reeling off seven straight points.
Cilic next plays Marcel Granollers of Spain, who beateighth-seeded Jack Sock of the United States 6-3, 6-1. Earlier, Gilles Muller of Luxembourg earned a spot in thelast eight against Federico Delbonis of Argentina. Muller beatFlorian Mayer of Germany 6-3, 6-2.