Updated

Indian Wells, CA (SportsNetwork.com) - Ukraine's Alexandr Dolgopolov stunned defending champion and world No. 1 Rafael Nadal on Monday to reach the fourth round of the BNP Paribas Open, the first Masters 1000 event of the year.

The 28th-seeded Dolgopolov posted a 6-3, 3-6, 7-6 (7-5) victory, his first against the Spaniard in six lifetime meetings. He lost in straight sets to Nadal last month in the Rio final.

Dolgopolov broke Nadal's serve for the fourth time in the match to go up 5-2 in the decisive set. Nadal won the next three games and held to force a tiebreak.

The reigning U.S. and French Open champion Nadal defeated Juan Martin del Potro in last year's Indian Wells finale. He also won the title here in 2007 and 2009.

Dolgopolov will next play 13th-seeded Italian Fabio Fognini, who battled past 23rd-seeded Frenchman Gael Monfils 6-2, 3-6, 7-5.

Four-time champion Roger Federer and former runner-up Andy Murray were a pair of hard-fought third-round winners.

The seventh-seeded former world No. 1 great Federer won his eighth straight match by getting past 27th-seeded Russian Dmitry Tursunov in a pair of tiebreaks, 7-6 (9-7), 7-6 (7-2), while the fifth-seeded Wimbledon champion Murray held off Czech Jiri Vesely in three sets, 6-7 (2-7), 6-4, 6-4, on the hardcourts at the beautiful Indian Wells Tennis Garden.

The recent Dubai titlist Federer titled here in 2004, 2005, 2006 and 2012, while Murray, who failed to reach a final in his first four tournaments this season, was an Indian Wells finalist back in 2009.

Australian Open champion Stanislas Wawrinka didn't have much of a struggle against 29th-seeded Italian Andreas Seppi. The third-seeded Swiss cruised to a 6-0, 6-2 win, his 13th in a row this season.

Tenth-seeded Canadian Milos Raonic, 11th-seeded German Tommy Haas and 17th-seeded South African Kevin Anderson also advanced.