In this photo by Rob Griffith, Spain's Rafael Nadal celebrates a four-hour, five-set comeback victory over American Tim Smyczek in the second round of the Australian Open late Wednesday night. The No. 3-ranked Nadal, a finalist in the tournament last year, had called for medical assistance in the third set after suffering stomach pain and was doubled over at times during the match due to illness or exhaustion. He said afterward it was a ''very tough night for me'' and praised Smyczek's sportsmanship. The No. 112-ranked qualifier had let Nadal replay a serve interrupted by a spectator's scream in the final game.