Murray entered the Gijon Open as a wildcardAndy Murray has reached the quarter-finals of the Gijon Open by coming from a set down to defeat Pedro Cachin.
Murray, given a wildcard for the tournament in Spain, defeated his Argentine opponent 2-6 7-5 7-6 (7-3).
The British number three will face Spanish third seed Roberto Bautista Agut or American Sebastian Korda in the last eight.
"I think I served well in the second and third sets but also I just fought very hard," Murray said afterwards.
"In the first set I wasn't playing my best and Pedro was serving very well for the first set and a half and I was really struggling to break serve.
"I changed a little bit the way I was returning and gave myself more opportunities to break and fought very hard to come back from a break down twice in the third set."
Former world number one Murray is competing in his first tournament since September's Laver Cup.
He made hard work of this win, failing to take five break points in the first set while Cachin, ranked 61st in the world, converted two of his three.
Murray improved in the second set before dropping serve twice in the third, but on both occasions he broke back immediately and went on to triumph in the decisive tie-break.
Gijon is one of the six one-year licensed tournaments taking place this season after the cancellation of the China leg of the ATP Tour because of ongoing Covid-19 restrictions.
Russian Andrey Rublev is the top seed as he looks to qualify for the season-ending ATP Finals for the third successive year.
