Top seed John Isner captured a 6-3, 6-4 win over fellow American Ryan Sweeting on Wednesday to move into the Delray Beach International Tennis Championships quarterfinals. The 11th-ranked Isner struggled through his first round win over wildcard recipient Jesse Levine on Tuesday because of the humidity, but was in better shape playing Sweeting. "Whenever, in the past, when I've played tournaments in humidity I've always struggled because I hadn't acclimated yet," Isner said. "But tonight I felt so much better than I did yesterday." Read more: http://espn.go.com/tennis/story/_/i...ernational-tennis-championships-quarterfinals