John Isner fights off challenge of Andreas Haider-Maurer in four sets

John Isner has secured a place in the third round of the Australian Open with a 6-4 7-6 4-6 6-4 victory over Andreas Haider-Maurer.

Isner was predictably dominant on serve early on in the match, and he made the crucial breakthrough in the fifth game as Haider-Maurer gifted the American the advantage with a sloppy service game.

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The 19th seed would lose just one point on serve in the entire first set, with Haider-Maurer powerless to prevent his rival from taking the opener.

Haider-Maurer continued to invite pressure on his own serve throughout the second, but Isner missed numerous chances to make the breakthrough before the tie-break.

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Isner fell behind early in the tie-break, but his powerful hitting allowed him to peg back his Austrian rival before moving into a commanding two-set lead.

The odds appeared to be stacked against Haider-Maurer, but a rare occurrence earned him a way back into the match as Isner lost his serve without scoring a point midway through the third set.

Haider-Maurer kept his composure in the face of some aggressive tennis from Isner to reduce the deficit and force his rival into a fourth set.

The battle of power continued in the fourth set, but an impressive challenge from Haider-Maurer came to a sudden halt when Isner broke to love in the 10th game to secure the victory.