HALLE, Germany (AP) -- Second-seeded Novak Djokovic overwhelmed Jurgen Melzer 6-1, 6-4 Friday to reach the semifinals of the Gerry Weber Open.

Djokovic will next play qualifier Olivier Rochus of Belgium, who came from a set down to defeat Benjamin Becker of Germany 6-7 (4), 6-3, 6-3.

Philipp Kohlschreiber, the runner-up last year, used 17 aces to down Andreas Beck 3-6, 6-3, 6-3.

He will face veteran Tommy Haas, who won another all-German showdown by defeating Mischa Zverev 7-6 (5), 6-2.

Haas, who will play in his first semifinal of the season, is coming off his best showing at the French Open in seven years. He reached the fourth round before losing to Federer after winning the first two sets.

Djokovic lost his two previous matches against Rochus, both in 2005.

"It's going to be interesting to play him again," Djokovic said. "He has a great game on grass, he's got a great touch and he moves very well. He played the qualifying rounds. so he's got a few matches on grass already."

Rochus is working his way back after shoulder surgery in October. He's played mainly challenger events since he resumed his career in February.

"I am more than delighted, it's fantastic for me," the 28-year-old Belgian said.

Rochus was on the verge of reaching the semifinals of the same tournament three years ago, when he had four match points against Roger Federer before losing to the eventual champion.

Federer pulled out of the tournament this year after winning the French Open on Sunday.

"That was never on my mind, I never thought about it. It was a different match today," said Rochus, who reached his first semifinal in more than two years.

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