INDIAN WELLS, Calif. (AP) -- Playing competitive tennis for the first time in over 18 months, Mardy Fish battled for 2 hours, 36 minutes Thursday before losing to fellow American Ryan Harrison, 6-4, 4-6, 7-6 (3) in the first round of the BNP Paribas Open.

Fish had two match points at 15-40 in the 10th game of the third set, but Harrison wiggled free. After both held serve to force the 12-point tiebreaker, Harrison won three points in a row to go up 5-2. Fish's double fault gave Harrison match point and the 22-year-old closed it out with an ace.

The 33-year-old Fish, once ranked No. 7 in the world, had not played on the ATP Tour since Aug. 20, 2013, because of heart problems that have plagued him since March 2012.

A finalist in 2008, when he lost to Novak Djokovic, Fish said that despite the long layoff the loss to Harrison ''stings a little bit.''

But there were positives.

''I've worked really hard in the past 3 1/2 months to get back in shape,'' Fish said, ''So, I don't have any issues sort of during a match or after a match. I worked extremely hard to put myself in the best position to not have to worry about things when I was out there - if I was out of shape or if I didn't feel well or if it was going to be a long match or a hot match or something like that, when a lot more things creep into your head.''

American wild-card Tim Smyczek was among those advancing as the men began play in this two-week, $10.7 million tournament, but two-time champion Daniela Hantuchova was among those eliminated on the second day of women's action. The 2002 and 2007 winner was a 6-4, 1-6, 6-3 loser to Klara Koukalova of the Czech Republic. Vera Zvonareva, the 2009 champion, also lost, 6-1, 6-1 to qualifier Polona Hercog of Slovakia, and Chinese qualifier Lin Zhu ousted 2010 French Open champion Francesca Schiavone of Italy.

The men will conclude their first round Friday, while the women begin second round play, highlighted by Serena Williams's return after a 14-year absence. Williams will face Monica Niculescu of Romania on Friday night.