Former US Open champion Marin Cilic was taken to four sets and five match points before reaching the second round of the Australian Open on Monday.
The Croatian sixth seed looked set for a cruising straight sets victory before dropping the third set against Canadian qualifier Vasek Pospisil.
Pospisil made things interesting in a tense fourth set tiebreaker before Cilic finally prevailed 6-2, 6-2, 4-6, 7-6 (7/5) on Hisense Arena.
It is the ninth time Cilic, the 2014 US Open champion, has reached the second round in Melbourne as he tries to better his semi-final appearance in 2010 where he lost to Andy Murray.
Cilic is coming off an outstanding 2017 where he lost to Roger Federer in the Wimbledon final and made the quarter-finals at Roland Garros along with climbing to a career-high ranking of four.