Top-ranked Novak Djokovic won the Monte Carlo Masters for the second time in three years by defeating sixth-seeded Tomas Berdych 7-5, 4-6, 6-3, in Monaco on Sunday.
Djokovic, who has lost only two matches in 2015, became the first player in tennis history to win the first three Masters tournament of the year after completing the Indian Wells-Miami sweep this spring.
In windy and humid conditions, both players struggled with their serve and made several unforced errors in a final that lacked rhythm and was suspended by rain.
Berdych put Djokovic on the back foot in the early stages with his powerful groundstrokes and forced the Serb into a deciding set for the first time this week but was ultimately made to pay for his erratic display.
With his 23rd Masters title, Djokovic extended his winning streak to 17 matches.
Top-ranked Serena Williams fought back from a set down to win her windy singles match over Sara Errani but couldn't produce another victory in the decisive doubles encounter as Italy beat the United States, 3-2, in a Fed Cup World Group playoff in Brindisi, Italy.
Italy's Flavia Pennetta and Errani defeated Williams and Alison Riske 6-0, 6-3.
"It was tough," U.S. captain Mary Joe Fernandez said. "They don't miss, they defend really well, and they make moves. And they play a lot more. Serena hasn't played a doubles match in a long time."
It was Williams' first career loss in the Fed Cup, dropping to 16-1 — 13-0 in singles and 3-1 in doubles.