Top seed and defending champion John Isner posted a quarterfinal victory Friday at the Hall of Fame Tennis Championships.

The 6-foot-9 American smacked 12 aces in getting past South African qualifier Izak Van der Merwe 6-4, 7-6 (7-2) on the grass courts at the International Tennis Hall of Fame.

Isner will meet the Ryan Harrison-Benjamin Becker winner in a semifinal here on Saturday, the same day Tennis Hall of Fame will induct its Class of 2012, including former players Jennifer Capriati, Gustavo Kuerten and Manuel Orantes.

The towering Isner beat diminutive Belgian Olivier Rochus in last year's Newport finale.

Saturday's other semi will pit Aussie Lleyton Hewitt against American Rajeev Ram, who was a surprise champion here in 2009. The long-time ATP star Hewitt is a former world No. 1 and two-time major titlist.