For a while there ASB Classic organisers must have been thinking "here we go again".

The bumper third day of action, in which all top four seeds were due to take the court following a first round bye, opened with the news the tournament's number one seed and defending champion Roberto Bautista-Agut had withdrawn due to a stomach virus.

A couple of hours later fellow Spaniard and four-time champion David Ferrer was also packing his bags after being edged by Dutchman Robin Haase in their second round match. So when world number 19 John Isner found himself struggling mid-way through his match against Tunisia's Malek Jaziri, it was beginning to look as if the ASB Classic had become the tournament where the top seeds fail to sprout.

After last week's disastrous run in the women's tournament, in which headline acts Serena and Venus Williams failed to progress beyond the second round, while the top six seeds were gone before the semifinals, the last thing organisers needed is a series of big-name capitulations in the men's draw.


It took a nerve-wracking third-set tiebreak, but Isner eventually snapped the trend.

After taking out the first set 6-3, Isner lost his momentum in the second as Jaziri did a better job of forcing his 2.08m opponent to run, taking advantage of the American's lack of mobility. Jaziri reversed the opening set scoreline to force a third.

Returning to his stengths in the third set, Isner looked more comfortable late in the game, but he was unable to break Jaziri, leading to a 6-6 stalemate. A tiebreak scenario was always going to favour Isner, with his big serve proving to be quite literally the ace up his sleeve. The American proved to have a few more cards to call on as well, with his last three points coming from backhand half-volley winners.

Despite the second set lapse, Isner said he was happy with the way he played today, particularly his composure on the big points.

"I very easily could have been on a flight to Melbourne tomorrow, I'm glad I'm not," said Isner, adding he would take the mentality that he is now playing with "house money" into tomorrow's quarterfinal against compatriot Steven Johnson.

Isner said the unexpected early exits of the Bautista-Agut and Ferrer does not give him any added confidence about his chances of claiming his third title in Auckland.

"I don't look ahead, I'm not good enough to look ahead."

Isner's 6-3 3-6 7-6 (6) win over Jaziri was one of three enthralling three-set battles on centre court in today's day session.

Ferrer and Haase set the tone for the day, with the Dutchman edging the Spanish veteran 2-6 6-4 7-6 (4) in just over two hours. Haase, who dispatched local hope Finn Tearney in the first round, started slowly as he struggled to find some venom with his first serve, but once he found more pace and better angles in the second set he proved more of a handful for Ferrer.

Marcos Baghdatis and Germany's Dustin Brown wrapped the proceedings with the most entertaining match of the day between two players renowned for their creative play and colourful on-court antics.

In a match played in good spirit throughout, Baghdatis, who wowed crowds in the night session the previous evening, recovered from a slow start to secure his place in the quarterfinal with a 4-6 7-6 6-4 win.

Tonight's evening session will feature fourth seed Jack Sock, who takes on US qualifier Ryan Harrison.