Melbourne, Jan 19: Australian Open champion Novak Djokovic started his title defence with a 7-6 (7-5) 6-2 2-6 6-1 victory over Jan-Lennard Struff on Monday.
Djokovic survived a scare on Rod Laver Arena, but the 16-time grand slam champion eventually moved into the second round at Melbourne Park.
Eyeing a record-extending eighth Australian Open title, second seed Djokovic will face either Tatsuma Ito or Prajnesh Gunneswaran for a spot in the third round.
World number 37 Struff presented a tricky opening test for Djokovic, especially with Craig O'Shannessy - the Serbian star's former chief strategist - now in his corner.
Struff, who had never beaten Djokovic, Roger Federer or Rafael Nadal, was not overawed, displaying aggression from the baseline and net.
Despite blinking first as Djokovic broke for a 4-2 lead and consolidated for a 5-2 advantage, Struff was unperturbed and reeled off three consecutive games, despite saving a set point along the way, to level the match and then force a tie-break.
Djokovic, however, managed to hold off the tenacious German in a tense and taxing breaker, using a wide serve to close it out at the second time of asking.
Struff was clearly feeling the effects when he quickly fell 2-0 behind at the start of the second, and Djokovic never relinquished the advantage before he broke again for a two-sets-to-love lead.
It seemed routine for Djokovic but he suffered an uncharacteristic stumble in the third as Struff's chances of a huge upset returned.
The pair traded breaks before the Djokovic serve went AWOL, allowing Struff to move 4-2 up before Djokovic served two double faults at 2-5, 30-30 to hand Struff a lifeline.
Normality was swiftly resumed in the fourth, however, Djokovic breaking in the opening game and again for a 4-1 lead before closing it out on the Struff serve to seal his 900th Tour level win.
STATISTICAL BREAKDOWN Novak Djokovic  bt Jan-Lennard Struff 7-6 (7-5) 6-2 2-6 6-1
WINNERS/UNFORCED ERRORS Djokovic – 44/28 Struff – 39/34
ACES/DOUBLE FAULTS Djokovic – 14/3 Struff – 13/7
BREAK POINTS WON Djokovic – 64% Struff – 80%
FIRST SERVE PERCENTAGE Djokovic – 65 Struff – 56
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE Djokovic – 77/50 Struff – 65/41
TOTAL POINTS Djokovic – 113 Struff – 91