Angelique Kerber began the defence of her Australian Open title with a nervy 6-2 5-7 6-2 victory over Lesia Tsurenko on Monday.
The German was triumphant in Melbourne 12 months ago in a breakout year that also saw her win the US Open and usurp Serena Williams as world number one.
Kerber returned to Rod Laver Arena and appeared in cruise control when she won seven consecutive games to take a set and a break lead against unfancied Ukrainian Tsurenko.
However, the top seed, who suffered early recent defeats in Brisbane and Sydney, saw her nerve desert her when serving for the match and a rejuvenated Tsurenko forced a decider.
An upset failed to materialise, though, as Kerber regained her composure to dominate the third and set up a second-round tie with Carina Witthoeft.
Kerber was initially slow to get going, but she was soon into the groove and a typically dominant display at the baseline saw her reel off five straight games to take the opener.
The German was riding the crest of a wave and a terrific drop shot saw Kerber break at the first time of asking in the second set and, after a simple hold, she appeared to be coasting into round two.
However, the top seed displayed her first sign of nerves after failing to convert match point at 5-4 as Tsurenko fought back to level the set.
That proved a momentum turner and Tsurenko, who survived two break points at 5-5, forced a decider when Kerber - who had already swatted away four set points - put a backhand into the net.
Kerber appeared more flat-footed and a sublime Tsurenko drop shot brought up break point in game four that she was unable to convert.
It proved a crucial miss as Tsurenko went wide with a forehand on break point in the next game to hand Kerber a 3-2 lead, which she quickly consolidated.
Tsurenko's resolve was ended when Kerber broke again for a 5-2 lead and there was no way back for the World No. 51 this time, the holder ultimately advancing in two hours and three minutes.
Kerber  bt Tsurenko 6-2 5-7 6-2
Kerber - 27/34
Tsurenko - 30/40
Kerber - 3
Tsurenko - 0
BREAK POINTS WON
Kerber - 5/11
Tsurenko - 2/8
FIRST SERVE PERCENTAGE
Kerber - 56
Tsurenko - 60
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Kerber - 70/64
Tsurenko - 64/47
Kerber - 99
Tsurenko - 81