DELRAY BEACH, Fla. (AP) -- Australian qualifier Marinko Matosevic beat No. 6 seed Alex Bogomolov Jr. of Russia 4-6, 6-1, 6-3 Wednesday to reach his first career ATP quarterfinal at the Delray Beach International Tennis Championships.
The 173rd-ranked Matosevic had 11 aces and won five of eight break points.
"It was a tough match and I'm happy to get through and make my first quarterfinal," said Matosevic, who next faces 2010 Delray Beach champion Ernests Gulbis. "I knew his game pretty well and he reaches a lot of balls, so I just had to keep staying aggressive.
"I played the big points well."
The 26-year-old has spent most of his career playing on the Challenger circuit.
Bogomolov had the best season of his career in 2011, starting the year at No. 166 and finishing at No. 34. Fellow players voted him the year's most improved player.
Bogomolov struggled throughout the match, including in his victorious first set.
Gulbis beat Steve Darcis of Belgium 6-7 (6), 6-1, 6-3 to reach his first quarterfinal of the season. The Latvian won 40 of 45 points on his first serve and fired 10 aces.
"Today was tough because I couldn't get my timing right in the first set," said Gulbis, who said the wind made it tough to play. "From one side it was much easier to get your serve going than the other side.
"I didn't play my best tennis today but I'm happy I won the match because I was fighting."
Top seed John Isner meets fellow American Ryan Sweeting on Wednesday night. Eighth seed Bernard Tomic of Australia will take on American qualifier Tim Smyczek in the second night match.