Three-set tussles have played a defining role in Andy Murray's comeback on the ATP Tour, and he had to come through another to see off Juan Ignacio Londero in reaching the second round of the Shanghai Masters.
Murray was impressive in making the quarter-finals of the China Open, where his run was ended by Dominic Thiem following a gruelling contest with compatriot Cameron Norrie in which the Scot appeared a spent force in the second set.
The former world number one, a three-time winner in Shanghai, needed to work just as hard to see off Londero, who won the first set but could not complete what would have been a memorable victory as Murray prevailed 2-6 6-2 6-3 in an engrossing battle.
As Murray continues to try to work his way back to the top of men's tennis, a rising star in the sport, Denis Shapovalov, set up an enticing second-round clash with Novak Djokovic by beating Frances Tiafoe.
Meanwhile, there was a surprise defeat for Marin Cilic, who was beaten in straight sets by Albert Ramos Vinolas.
MURRAY SCRAPS INTO THE SECOND ROUND
Three-time grand slam champion Murray was not shy about letting his frustration show as he was made to work extremely hard for his place in the second round by Londero.
Murray served poorly in the first set but found form in the second, though he rarely looked satisfied with his performance and shouted an expletive as he gave a break of serve back in the decider.
However, a searing cross-court forehand saw Murray break once more and he did not the let the initiative slip again, winning a match in which he seemed to battle himself as much as Londero in two hours and 17 minutes.
He had to save two break points to serve it out, securing a victory that books a meeting with Fabio Fognini, who overcame Sam Querrey in straight sets.
"I've always enjoyed playing here, I enjoy the faster conditions but it's a tricky one. Since I came back to play these are by far the fastest conditions I have played in and I struggled a bit with that early on, with my movement and stuff," Murray said.
"But it's nice to be back, nice to get the win and hopefully [I'll] start the next match a little bit quicker.
"I got better as the match went on so hopefully I'll be a bit better in the next match. I know what to expect, I know you can't hang back and let the opponent dictate. Try to be more aggressive.
"Fabio has had a great year, he's a very talented guy. I think he's playing for one of the last spots in London [ATP Finals] so I'm sure he'll be up for it. He played a very good match in the first round so it'll be a tough one."
SHAPOVALOV SET FOR DJOKO DUEL
Two players each expected to be future heavyweights met as Shapovalov faced Tiafoe, but it is the Canadian who is clearly further along in his development, and he provided evidence of that in a comfortable victory.
The world number 36 eased to a 6-4 6-2 win over the American, who won only two points against his opponent's first serve.
Shapovalov's win marked his first at the Masters 1000 tournament and means he will face world number one Djokovic for the third time this year.
Djokovic beat Shapovalov in four sets en route to winning the Australian Open and also defeated the 20-year-old in straight sets in Rome.
ROGER NEXT FOR RAMOS VINOLAS
Cilic would have faced Roger Federer in a rematch of the 2017 Wimbledon final had he seen off Ramos Vinolas, but did not have a break point as he was defeated 6-4 6-4.
It will now be the Spaniard who takes on the 20-time grand slam champion, who is eyeing a third Shanghai title.
Ninth seed Gael Monfils needed three sets to progress in his opening-round match with Lorenzo Sonego and 15th seed Nikoloz Basilashvili went the distance in his triumph over Radu Albot, but Diego Schwartzman suffered a shock loss to Vasek Pospisil.
Pospisil's fellow qualifiers Norrie and Jeremy Chardy also reached the second round, coming through against Kyle Edmund and Gilles Simon respectively.
Elsewhere in the draw, there were wins for Taylor Fritz, Cristian Garin, Hubert Hurkacz, Benoit Paire, Mikhail Kukushkin and Joao Sousa.