ROME — Venus Williams won in singles, and then lost in doubles with younger sister Serena.

Venus beat CoCo Vandeweghe 6-4, 6-3 in the first round of the Italian Open on Monday. She and Serena later lost to Andreja Klepac and Katarina Srebotnik of Slovenia 6-1, 7-5.

It was the first time the sisters had played doubles together since the 2014 U.S. Open. They are preparing an attempt at a fourth Olympic gold medal in doubles in Rio de Janeiro.

"We didn't play our best at the same time," Venus said. "That's not typical. Usually one of us is playing well. That helps the team a lot. Two of us are playing well, it usually goes our way."

In men's play, Milos Raonic beat Italian wild-card entry Marco Cecchinato 6-4, 4-6, 6-4.