Andy Murray came through a tense second-set tie-break to edge out Norwegian qualifier Viktor Durasovic in the Stockholm Open first round on Tuesday.
The former world number one needed three match points and saved a set point in the breaker to win 6-1, 7-6 (9/7).
"At the end it was just a big fight, and I managed to get the tie-break," said Murray. "It feels like he is playing better than 300 or so in the world."
The injury-hit 34-year-old, still bidding to climb from his current lowly ranking of 143, will face Italian top seed Jannik Sinner in the last 16.
"Sinner has had a fantastic season," Murray said. "He was very unlucky to not make the final eight (ATP Finals) in Turin.
"He loves playing indoors on hard courts, so it will be a big test for me."
Murray, playing on a wildcard, is hoping to bounce back this week from the disappointment of his tight opening loss to German Dominik Koepfer in last week's Paris Masters.
He was still a hot favourite against world number 354 Durasovic and raced through the first set.
The three-time Grand Slam champion broke in the opening game of the second, but Durasovic battled back.
He managed to stave off two match points in the tie-break but could not take a set point when leading 7-6 and Murray did enough to seal an enticing encounter with rising star Sinner