(Reuters) - Nick Kyrgios started his Brisbane Open title defence with a battling 7-6(5) 5-7 7-6(5) victory over American Ryan Harrison in the opening round on Tuesday.
Kyrgios' preparations for the season were interrupted by a spider bite that required hospital treatment last month and the Australian stuttered before firing 45 aces to overcome Harrison in a rematch of last year's final.
Kyrgios, whose season ended in October due to a niggling elbow issue, will look to hit top gear ahead of this month's Australian Open. He meets Jeremy Chardy next.
Andy Murray made a successful return to competitive tennis following a persistent hip problem, sealing a 6-3 6-4 win over local hope James Duckworth.
Murray, champion in his previous two appearances in 2012 and 2013, will look to extend his winning streak in the tournament to 11 matches when he meets Russian Daniil Medvedev next.
Top seed Rafa Nadal said he was raring to go following an injury hit 2018 that saw him contest only nine events but win five titles including a record-extending 11th French Open title that took his Grand Slam tally to 17.
"It was a tough season in terms of injuries... I didn't have the chance to play as often as I would like," Nadal, who did not play after retiring against Juan Martin del Potro in their U.S. Open semi-final in September, said.
"On the other hand, I won five events out of nine I played. It was a great level of tennis every time that I was on court. So that's great news. I enjoyed it a lot."
Nadal was plagued by hip, knee, abdomen and ankle problems last season but said he still had plenty to offer.
"I believe I have a lot of tennis to play in my career, and I really feel my body is not going worse every year," Nadal, who plays France's Jo-Wilfried Tsonga on Thursday, added.
In the women's competition, double Wimbledon champion Petra Kvitova was made to work before she downed American Danielle Collins 6-7(6) 7-6(6) 6-3 in a little over three hours.
Johanna Konta struggled with patchy form last season but the Briton began the New Year with a bang, downing third seed Sloane Stephens 6-4 6-3.
"That was a tough match. The first three games took about half an hour," Konta, who takes on Australia's Ajla Tomljanovic next, said. "I'm happy I was able to maintain my level consistently throughout."
U.S. Open champion Naomi Osaka beat local qualifier Destanee Aiava, hitting nine aces during a routine 6-3 6-2 victory.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Christian Radnedge)