Murray, who hasn't won since October, was playing his fourth match of 2024 on Tuesday but delivered a disappointing performance as Machac beat him 7-5 6-4, with both players far from their best.

Earlier this year, Murray admitted this season could be his last on the ATP tour if he is "not enjoying it" but last week he responded to criticism on X, formerly known as Twitter, by vowing "I won't quit".

The three-time Grand Slam champion is set to take two weeks off before next playing at the Qatar Open in Doha in the week beginning February 19 - live on Sky Sports Tennis.

• Emma Raducanu in action on Wednesday against Ons Jabeur live on Sky
• What tennis is live on Sky? | Tennis scores and schedule
• ATP Tour calendar for 2024 | How to watch Sky Sports Tennis
• Stream Sky Sports with NOW | Get Sky Sports on WhatsApp

Machac capitalised on several Murray unforced errors to break in the third game of the opening set but the Briton broke back to make it 3-3 and the next four games were shared with the scores now at 5-5.

However, Murray made further mistakes in the 11th game as he continued to frustratingly find the net so Machac broke his opponent and held serve to take the first set in 52 minutes.

The crowd inside the Palais des Sports de Marseille urged Murray on but Machac broke early in the second set. Machac offered up break point to Murray in the sixth game but saved it with some attacking groundstrokes to lead 4-2.

Despite Murray raising his game, Machac managed to comfortably hold serve to the end which was enough to book a spot in the second round against Italy's Lorenzo Musetti.

"It is special to share the court with such a great player, such a legend. I'm super happy that I could play against him and to win is a bonus," said Machac, who was playing Murray for the first time.

"I remember lots of matches from Andy when he faced match points but he won the match. So many times when I had 40-0 I played a normal shot, like it was 15-15."

Watson wins in Abu Dhabi and Dart progresses in Transylvania

There was success for British players on Tuesday, though, as Heather Watson won her first main draw match of 2024 with a 6-3 7-5 victory over Veronika Kudermetova at the Abu Dhabi Open.

Watson won two qualifying matches to reach this stage, including an impressive win against former Grand Slam champion Sofia Kenin.

The 31-year-old, who will face Cristina Busca next on Thursday, said: "I just focused on what was in my control and kept as aggressive as I could.

"I played really well and had fun. Every player here is so good and playing the qualifiers helped. I knew the conditions and felt really prepared."

Naomi Osaka was back in action for the first time since the Australian Open but lost to American Danielle Collins 7-5 6-0 in Abu Dhabi.

The four-time grand slam champion made her comeback last month following the birth of her first child, reaching the second round of the Brisbane International before losing a close contest to Caroline Garcia in her opening match at the Australian Open.

Rallies were few and far between in a first set dominated by serve until Collins - who plans to retire at the end of the season - claimed the crucial break at 5-5.

From there, the former Australian Open finalist ran away with the contest - Osaka committing 20 unforced errors and looking dispirited as she dropped serve four times in a row and Collins booked a second-round meeting with top seed Elena Rybakina.

Britain's Harriet Dart secured a straight sets win over Hungary's Anna Bondar to book a place in the second round of the Transylvania Open.

Dart came back from a break and 4-2 down in the first set to win 6-4 7-6 (7-0) and will play Emiliana Arango or fifth seed Elisabetta Cocciaretto.

The 27-year-old also won two qualifying matches to get into the main draw of the WTA 250 tournament.

Sky Sports launches tennis channel

Sky Sports has confirmed a new home for tennis in the UK and Ireland, with Sky Sports Tennis to launch on Sky and NOW from February 11, making tennis content available every day for fans.

Sky Sports will broadcast more live tennis than anywhere else, bringing over 4,000 matches from more than 80 tournaments a year on the ATP and WTA Tours, as well as full US Open coverage.

Sky Sports Tennis will be available to Sky Sports customers with Complete, Action and Arena packages, with viewers able to access multiple live court streams at the same time via the Sky Sports mobile app, the Sky TV app or red button and on NOW Bonus Streams, giving access to more live matches.

Get Sky Sports on WhatsApp

You can now start receiving messages and alerts for the latest breaking sports news, analysis, in-depth features and videos from our dedicated WhatsApp channel. Find out more here...