DELRAY BEACH, Fla. (AP) -- At 6-foot-11, Ivo Karlovic, has served his way out of plenty of predicaments.

On Sunday, the tallest tennis professional player on record did so again, hitting 13 aces and saving all seven break points he faced to beat Donald Young 6-3, 6-3 in the Delray Beach Open for his sixth career ATP Tour title.

The fourth-seeded Karlovic, six days shy of his 36th birthday, became the oldest champion in the 23-year history of the tournament. He's the oldest ATP World Tour singles winner since Jimmy Connors in Tel Aviv in 1989 at age 37.

''It is unbelievable, just really satisfying, especially at my age,'' said Karlovic who last season went 0-4 in tour finals. ''This gives me a real boost of confidence.''

In five matches this week Karlovic never lost his serve, winning 56 consecutive games. He also served 91 aces, breaking his own tournament record of 89 aces, served when he lost in the final in 2010 to Ernests Gulbis. In 14 matches this season Karlovic has dropped serve just four times.

Young did his best to force Karlovic into baseline rallies so that he could maneuver his way to the net, a tactic that had been effective in his previous matches. But the Croat, who lives in nearby Plantation, forced the issue by lunging at every opportunity.

Serving at 3-3 in the first set, Young elected to let a Karlovic backhand passing shot go long. Instead, the ball landed inside the baseline. Young, clearly unnerved, double-faulted on the next point and was broken when Karlovic approached and knocked off a forehand volley winner.

Young had a chance to break back in the next game when Karlovic hit three double faults. But he also hit three aces, including two in a row to win the game.

''You don't get much rhythm in rallying with him,'' said Young, who was attempting to win his first ATP title. ''It's a weird type of feeling. You just can't sink your teeth into it.''

When Young was broken to go down 2-0 in the second set, he threw his racket down in disgust. When Karlovic saved three more break points to hold for a 3-0 lead, the American simply looked weary. Six games later, he closed out the match with three more aces, two of them clocked at 142 mph.

Bob and Mike Bryan won their 104th career doubles title, topping Raven Klaasen of South Africa and Leader Paes of India 6-3, 3-6, 10-6. The 36-year-old twins, ranked No. 1 in the world for the last six years, have played in 155 career finals together.