Andy Murray's progress to the second round of the Australian Open was far from easy as he had to battle against American teenager Ryan Harrison.
The Briton started sluggishly, tamely losing the opening set before eventually prevailing 4-6 6-3 6-4 6-2.
Murray broke early in the second set and was comfortable thereafter, sealing the win in three hours and 12 minutes.
He will next play Edouard Roger-Vasselin on Thursday after the Frenchman beat Xavier Malisse.
Fourth seed Murray, playing a major tournament under the watchful eye of new coach Ivan Lendl for the first time, will hope to improve on his opening-round performance.
Harrison, regarded as one of the game's up-and-coming talents, caused Murray major problems in the first set as he broke in the fifth game, eventually taking the opener in 51 minutes.
Murray admitted afterwards that he had to "dig deep" at the start of the second.
"He came out playing great tennis, going for his shots and hitting big," said the Scot after a gruelling encounter in sweltering conditions on Hisense Arena.
"This court is tough - there's very little shade. We had a few long rallies and he made me do a lot of running. I'll need to make sure in my next match that I play closer to the baseline.
"He [Harrison] is very good already and he's getting better. I started to play better towards the end. I had a few nerves early on. You want to play your best tennis towards the end of the tournament so that's what I'll try and do."
There was a noticeable reduction in outbursts from Murray towards his on-looking back-up team during his struggles, which was perhaps due to the presence of eight-time major winner Lendl.
Murray improved considerably from the second set onwards, breaking Harrison after an energy-sapping fourth game and serving out confidently.
The momentum remained with Britain's sole remaining player in the singles draw and he earned two break points in the opening game of the third set, ruthlessly taking his first break chance when Harrison fumbled at the net.
A Murray victory seemed inevitable and he swiftly established a 3-1 lead in the fourth before breaking again for 5-2 and serving out.
