Croatia's Ivo Karlovic became the oldest ATP winner since Jimmy Connors in 1989 when he captured the Delray Beach Open final on Sunday.

The 35-year-old used his prodigious serve to break American opponent Donald Young three times for a 6-3 6-3 victory on the Florida hardcourt.

Karlovic, who turns 36 on Feb. 28, is the oldest winner since Connors won in Tel Aviv at the age of 37, according to the ATP.

It is Karlovic's sixth career title and it keeps the event in Croatian hands following last year's victory by Marin Cilic, who later in the season won the U.S. Open.

"It is really satisfying. At my age to do this is an unbelievable feeling and this gives me a boost of confidence to go into other events," Karlovic told reporters after beating Young in 69 minutes.

Karlovic does not know how long he can continue at such a high level, but says he is as fit as when he was in his late 20s.

"I am healthy," he said. "I feel fast, strong. I don't know how many more years I can do this but for now I am feeling good. In all the tests I am like eight years ago."

The 6-foot, 11-inch (211cm) Croat used his height to pound 91 aces for the tournament and remain unbroken in 56 service games, though he came closest to dropping serve when he was down 0-40 in the eighth game of the first set against Young.

"I was able to get out of it. I was also a little bit lucky," he said. "After that game I knew it would be easier because that game I did a lot of double faults and I was able to get out of it."

Young, who remains without an ATP title after two final appearances, said it was difficult to read where Karlovic was going to place his serve.

"He kind of tosses in the same spot and can hit all the spots on the court," Young said.

"You look and see some tendencies. I was able to pick quite a few, but just not when it actually mattered.

"He played well. He beat me. I didn't play the best I wanted to play, but all credit to him."