Second seed Rafael Nadal [ Images ] ground down German Philipp Kohlschreiber to win a tough match 7-5, 6-3, 4-6, 6-2 in the Australian Open [ Images ] second round on Thursday.

Nadal was forced to work extremely hard by the 23-year-old world number 61, who slugged it out with the Spaniard in the late match on Rod Laver Arena which finished at 0130 local time.

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Nadal, seeking a first Australian Open title, looked to be heading for a quick victory at two sets up but Kohlschreiber used his superb forehand to great effect to take the third set as both players struggled to hold serve.

Nadal, French Open [ Images ] champion in 2005 and 2006, raced into a 4-0 lead in the fourth but Kohlschreiber still refused to lie down, clawing back two games before the Spaniard sealed victory on his second match point in three and a half hours.

Nadal will play Switzerland's [ Images ] Stanislas Wawrinka, the number 31 seed, in the third round.