Novak Djokovic defeats German rival to take first step towards defending Australian Open title
The second-seeded Serb faced fierce resistance from his lower-ranked rival in the match opener, where a tie break was needed to determine the winner.
The more experienced Djokovic took the upper hand in a nail-biting ending to the first set, taking the lead in the first-round match at the season-opening major.
The second set was a walk in the park for the 16-time Grand Slam winner, who got full control of the game and broke his opponent twice to take the second set 6-2.
Despite a relatively easy win in the previous set, Djokovic stumbled in the beginning of the third, allowing Struff to make an early break to take a confident 2-0 lead.
The 32-year-old evened the score, before twice allowing Struff to take his serve again and create a surprising four-game lead, enough for the German player to win the third set 6-2.
After that relative on-court failure Djokovic made a stunning comeback, dispatching his 29-year-old opponent in the fourth set 6-1 to earn a place in the second round of the major tournament.