JOIN USDel Potro picks first win in a year
The 22-year-old Argentine has played only two tournaments since having surgery last May on a wrist injury that hampered his Australian Open campaign last year, losing in the first round in both. Del Potro, who won the 2009 US Open final against Roger Federer, showed great determination after trailing by a set and again in the second set tiebreak.
The third set was just as close and Del Potro was forced to save six break points before appropriately clinching victory with one of his savage flat forehands.
Earlier, defending champion and second seed Marcos Baghdatis pulled out of the tournament with a groin strain.
In the women's draw, local grand slam hopeful Sam Stosur delighted the centre court crowd by downing Yanina Wickmayer of Belgium 7-5, 6-4.
The world number six, a French Open finalist last year, will meet twice grand slam champion Svetlana Kuznetsova in the second round.
Two other women's seeds had more disappointing days, fifth seed Francesca Schiavone losing 6-7, 6-1, 6-2 to Russian Alisa Kleybanova and sixth seed Jelena Jankovic also beaten in three sets, 7-5, 2-6, 6-3 by France's Aravene Rezai. Seventh seed Victoria Azarenka though scraped through 2-6, 6-2, 6-4 against Ekaterina Makarova of Russia.
Kohlschreiber advances
Germany's Philipp Kohlschreiber overcame a slow start to advance to the second round of the Auckland Classic with a 2-6, 6-3, 6-1 victory over Argentina's Carlos Berlocq.
Spain's Tommy Robredo, who made the final on the central Auckland courts in 2007, was forced into a unexpected battle against New Zealand wildcard Michael Venus in an earlier match before coming through 6-,7 6-3, 6-0.