Andy Murray insisted he can compete at the top level as the former world number one warned the days of him progressing deep in tournaments again are on the horizon after stunning Jannik Sinner at the Stockholm Open.

Murray claimed his second top-10 win of the year after upstaging top seed Sinner 7-6 (7-4) 6-3 en route to the quarter-finals on Wednesday.

A three-time grand slam champion, Murray fended off the only break point he faced to close out another impressive victory in two hours, 10 minutes midweek.

Many questioned Murray's future in tennis and his ability to return among the contenders on the ATP Tour, having been devastated by injuries – the 34-year-old underwent hip resurfacing in 2019.

However, Murray is oozing confidence as he prepares to meet Tommy Paul for a spot in the semi-finals of the ATP 250 event.

BIG WIN ??@andy_murray beats top seed Jannik Sinner 7-6, 6-3 to make the quarter-finals in Stockholm!

: @sthlm_open #StockholmOpen pic.twitter.com/jOlUIgx5zB
— ATP Tour (@atptour) November 10, 2021

"I'm convinced I can play … well, I can. I'm playing at the top level and I'm winning matches against the best players in the world," said Murray.

"The ones that I'm losing, I'm pushing the best players in the world. That argument is finished. I can compete at the top level."

Currently ranked 143 in the world, Murray has a 15-13 win-loss record this year and has not claimed a title since October 2019.

Murray: "I said in the last few weeks, it's coming. It's coming.

"I don't know if it will be this week or the beginning of next year, but I'm going to be pushing and getting deep in tournaments again."