Former world number one Lleyton Hewitt hammered out a warning to his rivals for next week's U.S. Open as he demolished Peru's Luis Horna 6-3, 6-1 to win the Long Island Cup on Sunday.

The second seed, who accepted a late wildcard entry to the event, was ruthless as he crushed Horna's hopes of a first ATP Tour title to clinch his fourth tournament win of the year and 23rd of his career.

"I knew it was going to be a tough match today, even if the score didn't suggest it," Hewitt said. "You have to give a lot of respect for Luis, the way he got to the final, but I played well.

"I felt like I was right on top of him from the start, and I was not under much pressure on my serve, which is always a good sign."

The Australian lost just two points on his serve as he raced through the first set in 40 minutes, and took complete control when he broke in the second game of the second set.

Ninth seed Horna came from a set and 2-0 down to beat two-time defending champion Paradorn Srichaphan in the semi-finals on Saturday but, after saving one break point in the fifth game, Hewitt raced away for victory in one hour, 19 minutes.

The second seed belted down 12 aces, eight of them in the second set, as he clinched back-to-back titles after his win in Washington and extended his winning streak to 10 matches.

COMING TOGETHER

"I feel like my game's coming together well but it's not going to be easy next week (at the U.S. Open)," said the Australian.

"It's seven best-of-five matches, in humid conditions and it's a gruelling surface. You have to be ready to back up matches if it rains, so you have to be mentally focused and prepare for everything."

Along with Andre Agassi, Hewitt decided not to play at the Olympic Games.

"Flying to Athens from Australia, having played in Toronto, the previous week -- I've had viruses in the past and I didn't want to risk anything happening to me in the run-up to the U.S. Open," he said.

For Horna, it was simply a question of running out of steam after a tough week.

"I wasn't nervous, I was just really tired today. I had a game plan but, after I realised my legs weren't moving the way I wanted them to, that didn't really matter," he said.