Ivo Karlovic rallied from a set down on Tuesday to subdue American John Isner and slip into the third round of the New Haven hardcourt tournament.

The 29-year-old Croatian veteran, seeded number two at the tournament, pulled off a 6-7 (7/4), 6-3, 6-4 come-from-behind victory over the unseeded Isner in a match between two of the tallest players on Tour.

"Now, I know how everybody else feels when they play against me," said the gangly Karlovic who gunned down 17 aces to Isner's 13.

Karlovic is now pitted to meet Slovanian qualifier Luka Gregorc, who posted his first ATP Tour victory of the season after beating Argentine's Jose Acasuso 6-4, 6-4 earlier on Tuesday.

As expected, both players held stubbornly onto their deliveries. Isner ran away with the set in a close tie-breaker.

The 6-foot-10 Karlovic, who is enjoying a career-high rank of number 14 in the world, fought his back into the match, turning the tables on the inconsistent Isner with his thunderous serve and more steady game.

In the ensuing set, Karlovic broke Isner one last time in the 9th game when Isner clunked an easy forehand volley into the net. He served out the contest in the following game.

"I needed to return better," said a dejected Isner, ranked number 124 in the world. "I didn?t make enough first serves when I needed to."

Also on Tuesday, number eight seed Mardy Fish, a runner-up last year, beat fellow-American Wayne Odesnik 6-1, 4-6, 6-1, fourth-seeded Russian Igor Andreev trounced Belgium?s Olivier Rochus 6-3, 6-4 and Croatian Marin Cilic, the number six seed, hardly broke a sweat when Viktor Troicki of Serbia, trailing 2-1, retired because of a back injury.

On the women's side, third-seeded Frenchwoman Marion Bartoli was in quite a bit of hot water against Bulgarian Tsvetana Pironkova before prevailing 2-6, 6-4, 7-5, fellow-countrywoman and former world number one Amelie Mauresmo had as tough of a day, battling through Estonian Kaia Kanepi 6-2, 6-7 (7/3), 6-2.

"I felt I had the match under control," Mauresmo said. "I let her dictate play. My serve was shaky. My returns not great. At the end, I felt more dominant. It's just shame I didn't close it out in two sets."