Djokovic loses his cool again during win at Italian Open

Rome: Less than two weeks after getting defaulted from the U.S. Open, Novak Djokovic lost his cool again midway through a 6-3, 4-6, 6-3 win over German qualifier Dominik Koepfer in the Italian Open quarterfinals Saturday.

When Djokovic was broken at love to even the second set at 3-3, he slammed his racket to the red clay in anger.

With the frame broken and the strings all mangled, Djokovic was forced to get a new racket and received a warning from the chair umpire.

Djokovic had already appeared frustrated the previous game, when he glared toward the umpire following a couple of overrules and a point that was ordered to be replayed.

The top-ranked Djokovic had said Monday that he learned a big lesson after he was thrown out of the U.S. Open for unintentionally hitting a line judge in the throat with a ball in a fit of anger.

Djokovic also acknowledged then that I have outbursts and this is kind of the personality and the player that I have always been. The 97th-ranked Koepfer, who screamed at himself in frustration throughout the match, was also warned for misbehavior early in the third set.

Aiming for his fifth title in Rome, Djokovic's semifinal opponent will be Casper Ruud, who eliminated local favorite Matteo Berrettini 4-6, 6-3, 7-6 (5) in a match that lasted 2 hours, 57 minutes.

Nine-time Rome champion Rafael Nadal was playing Diego Schwartzman later in the other half of the draw.

Ruud is the first Norwegian to reach the semifinals of a Masters 1000 tournament. His father, Christian

Ruud, got as far as the quarterfinals of the Monte Carlo Masters in 1997.

While fans have not been admitted to the tournament yet -- Italy's sports minister said Friday that 1,000 spectators will be allowed in for the semifinals and finals -- workers, family members and other onlookers inside the picturesque Pietrangeli stadium provided some support for Berrettini, who is from Rome.

Nicola Pietrangeli, the 1957 and 1961 Rome champion and the man the stadium is named after -- was also among those sitting on the white marble stands.

There would have been a lot more adrenaline with fans, Berrettini said.

since the tennis restart and 12-0 overall stretching back to February.