Andy Murray was a relieved man after holding off two match points before eventually seeing off big-serving American John Isner at the Cincinnati Masters.
The Scot dropped the opening set in a tie-break, but forced a decider by clinching the second 6-4.
The number eight seed faced two match points on serve at 6-5 down, although he managed to hold before seeing off Isner is a second tie-breaker.
Character was key for Murray and the 27-year-old was pleased with how he handled the conditions and how he responded to the pressure in the final set.
"It was a big win for me," Murray told Sky Sports after setting up a quarter-final tie with Roger Federer. "He plays extremely well here.
"Returning his serve, especially his second serve, in these conditions is very challenging so I did well to fight back.
Very good match
"I felt like I played a very good match. I served well, I moved well, I was hitting the ball clean from the back of the court and when I was challenged at the end of the third set I responded well, that's important.
"It's all about winning right now, I don't really care how I play, I just try and keep getting wins."
Murray was also full of praise for his opponent, whose big serve had caused the 27-year-old problems all match.
"He has the best serve," he added. "He serves huge first serves and the difference between him and the other guys is the second serve.
"Her serves quite a lot of second-serve aces, he gets good work on the second serve.
“I was trying to take it early and even still it's bouncing up round the shoulder. If you take a couple of steps back, it's well above your head."
Watch Andy Murray play Roger Federer for a place in the semi-finals of the Cincinnati Masters live on Sky Sports 3 from midnight.