Updated

Indian Wells, CA (SportsNetwork.com) - American Ryan Harrison fought past compatriot Mardy Fish as the men's portion of the BNP Paribas Open commenced Thursday in the California desert.

Harrison defeated Fish, who played in his first ATP-level tennis event since August 2013 due to heart and anxiety issues, 6-4, 4-6, 7-6 (7-3) on the hardcourts at the Indian Wells Tennis Garden.

The former world No. 7 Fish was the 2008 Indian Wells runner-up to Novak Djokovic.

Australian James Duckworth beat Dominic Thiem of Austria 7-6 (7-5), 6-1; Jarkko Nieminen downed Thiemo de Bakker 7-6 (7-3), 6-4; Edouard Roger-Vasselin defeated Marinko Matosevic 5-7, 6-4, 6-3; and Daniel Gimeno-Traver battled past Sam Groth 7-6 (7-5), 7-6 (8-6).

American Tim Smyczek bounced German Benjamin Becker 6-3, 7-6 (7-4), while last week's Canadian Davis Cup hero Vasek Pospisil was leading Mikhail Kukushkin 6-4, 4-2 when the Kazakhstanian player retired. Pospisil will encounter fourth seed Andy Murray in his next outing.

Meanwhile, Argentine Juan Monaco snuck past Russian Teymuraz Gabashvili 6-2, 3-6, 6-3 and Croat Ivan Dodig topped Portuguese Joao Sousa 6-3, 7-5.

Additional winners on Thursday included Adrian Mannarino, Borna Coric, Thanasi Kokkinakis, Federico Delbonis, Jurgen Melzer, Albert Ramos-Vinolas and Marcos Baghdatis.

This week's top seeds are the "Big Four" -- Novak Djokovic, Roger Federer, Rafael Nadal and Murray. The three-time champion Djokovic beat the four- time titlist Federer in last year's marquee final. Nadal, like Djokovic, also owns three Indian Wells titles.

The winner of this $5 million event will collect $900,400.