Frenchman Gregoire Barrere admitted he was going a “bit crazy” during his ASB Classic first round match against American John Isner as he watched a barrage of huge serves fly past - often near head height.

On the ATP tour, there aren’t many tougher assignments than facing Isner’s serve. But it is even worse when you are on a slick indoor court, with the ball skimming and the wind and sun taken out of the equation.

That was the predicament for French qualifier Barrere, as their match went inside on Tuesday due to an adverse weather forecast.

But he prevailed against considerable odds - coming back from a set down, then a dangerous deficit in the second set tiebreak - to eliminate the sixth seed 6-7(3) 7-6(5) 6-3 in two hours and 18 minutes.

Barrere was jubilant after a considerable psychological test, as world No 41 Isner can be a formidable opponent.

Breaking his serve can sometimes seem impossible, and that is a big reason why, with an otherwise fairly limited game, he has three wins over No 1 ranked players (Novak Djokovic twice and Rafa Nadal) as well as a victory over Roger Federer when he was No 2.

No one on the ATP tour has served more aces than the 2.08m American. He has banged down more than 14,000 at an average of more than 18 per match and, perhaps even more impressively, he has won 80 per cent of points when the first serve lands.

That effectiveness was shown again on Tuesday.

There were many times when Barrere gained an opening – to 15-30 or 0-30 – only for the 37-year-old to serve his way out of trouble.

“Yeah, I was going a bit crazy after that, every game,” said Barrere. “But my coach said to me to stay calm and keep trying. And that’s what I tried and I was happy that it worked at the end because there was a lot [of opportunities]. I tried not to be too frustrated and it worked in the end.”

It was a significant victory for the world No 88, especially given Isner’s record of two titles, a semi-final and four quarter-finals in Auckland.

“He’s a very tough opponent, especially on indoor hard court, but it’s also my best court. So I knew I had a chance against him.”

The key, ironically, was the Barrere service game, as he was rock solid - never giving up a break opportunity - if not as spectacular, with 10 aces compared to 28.

“The main thing was to [hold] my serve and then to try the return,” said Barrere. “I tried to stay focussed.”

The 28-year-old, who has yet to win an ATP title (Isner has 16) said the qualifying matches had also been vital, at this early stage of the season.

The loss of the first set was tough to take, as Isner saved a break point, then a set point at 4-5 down, before clinching the tiebreak.

A second tiebreak seemed inevitable, as neither player forced a break opportunity.

Isner was two points from victory at 5-3 up in the tiebreak before Barrere dug himself out.

He was partly helped by a forehand winner off the edge of the racquet but also showed commendable grit to win four straight clutch points.

“I had a bit of luck [but] sometimes you need luck to beat that guy,” said Barrere.

He then broke Isner in the fifth game of the final set, before converting his first match point.