An ailing Lleyton Hewitt revealed he was just moments away from pulling the pin on his Sydney International title defence on Monday before battling back from the brink to beat lowly-rated American Vincent Spadea.

Struck down by a stomach bug for the past two days, Hewitt overcame a sluggish start to triumph 2-6 7-5 6-3 over the world No.75 in one hour and 53 uncomfortable minutes.

Afterwards, the 24-year-old revealed he considered ending his campaign for a fifth Sydney title when trailing 5-2 in the opening set of his first-round match.

The clearly distressed tournament top seed remained hunched over in his chair for close to 10 minutes during an injury timeout, but eventually chose to fight through the pain.

"I actually thought it was getting a bit dangerous out there to try and keep playing on," said Hewitt, who suffered a shock second-round loss in the Adelaide International last week but has only lost once in five years on hardcourts here at Olympic Park.

"I was probably only a couple of points away from having to walk off the court. I was tossing up, was it really worth it, with (the Australian Open) next week.

"To my credit, I hung in there and tried to get through knowing that I had a day off tomorrow. That was a huge factor in the back of my mind. Hopefully it's at its worst today."

Hewitt said the pain was nearly as bad as when he played a Hopman Cup tie in 2002 before being diagnosed with chicken pox.

The world No.4 was hopeful the bug would disappear before his second-round clash with Austrian Jurgen Melzer on Wednesday, but admitted the illness was a bit of a worry ahead of the Australian Open.

Hewitt served 10 double-faults and made 57 unforced errors in just his third match back after a three-month injury and family break. Before Adelaide, Hewitt had not played a tournament since September because of a groin injury and toe surgery, and then the birth of his first child, Mia, with new wife, actress Bec Cartwright.

Spadea, who also lost in three sets to Australian Mark Philippoussis in the first round of the Adelaide International last week and is infamous for losing a record 21 consecutive matches on the ATP tour in 1999-2000, had 14 break points throughout the contest but could only convert three.

Hewitt converted three of five into breaks, including one to take the second set and another decisive break to go ahead 5-3 in the decider.

The Australian avoided a second-round meeting with Argentine sparring partner Juan Ignacio Chela after the South American lost his first-round match 6-1 7-6 (7-1) to Melzer earlier today.

He remains on track to meet fellow Australian Chris Guccione in the quarter-finals after the 20-year-old Victorian matched his efforts of 2004 in the Sydney International by upstaging Spanish fifth seed and former world No.1 Juan Carlos Ferrero 4-6 6-3 7-5.

Guccione plays either Belgian Kristof Vliegen or Andreas Seppi of Italy in the second round.

Meanwhile, Swedish third seed Thomas Johansson has withdrawn from the tournament with a right shoulder injury, allowing Spaniard Fernando Verdasco to move into the second round.

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