Join us for that match tomorrow. Thank you for your company today. It's been another US Open experience to forget for Heather Watson. Goodbye for now... but remember you can still listen to Radio 5 live sports extra commentary into Monday evening (UK only) via this page. 

Murray, though, has defended Kyrgios, telling BBC Sport: "I don't think he's a bad guy. He's just got to learn a little bit and he'll be fine."

Image source, Getty Images

Australia's Kyrgios, ranked 37th in the world, has had torrid past few weeks.

The 20-year-old was fined and given a suspended ban for comments made about Stan Wawrinka's girlfriend during their recent match in Montreal.

Image source, Getty Images

So, with Heather Watson out, the British focus turns elsewhere. Andy Murray, who won the US Open in 2012, begins his campaign tomorrow against Nick Kyrgios, tennis' enfant terrible de nos jours. We'll have live text commentary of that right here - keep an eye on the website for details.

Matthew Vernon:  Not good enough from Heather today. She had more than enough chances to win that match. Needs to find a ruthless streak.

A very disappointing day for Heather Watson, who must have thought she had a good chance to end her disappointing record at Flushing Meadows.

"It's a match she should have won," former British number one Greg Rusedski told Sky Sports. "She wasn't confident. She wasn't willing to come forward enough. If she'd come forward and taken a few more risks there, she might have turned that match around. She'll be bitterly disappointed."

Abu Ali:  Hard to believe this is the same Heather Watson who was serving to knock out Serena at Wimbledon!

Andrew Priestley:  If Heather Watson wants to become a top level player she has to learn how to win the big points at the big moments in matches.

"I thought the match might have lasted longer," says an evidently surprised Davis as she conducts a post-match television interview on court. 

It's a moment of history for the American, who reaches the second round at Flushing Meadows for the first time. She will face 13th seed Ekaterina Makarova next. The Russian, a semi-finalist at Flushing Meadows last year, beat Brazil's Teliana Pereira 6-3 6-3.

Davis gets a double mini-break for a 3-0 lead as Watson first nets an attempted forehand down the line, and then gets dragged around in a long rally as the American wears her down. A long forehand from Watson, followed by a winner down the line from Davis, just about ties it up. To compound the British number one's pain, her opponent thumps a forehand across court into the corner. Davis is one point from victory.

Ana Ivanovic is a goner. The Serbian seventh seed loses 6-3 3-6 6-3 to Dominika Cibulkova. Ivanovic received treatment for a foot injury during the match.

A cross-court volley gives Watson a good start... but Davis will not go away, and responds with a huge forehand winner. Another cross-court shot from Watson is followed by a netted backhand from Davis for 40-15. The Briton holds firm in the next rally as Davis nets again - and once more, we're into a tie-break.

Image source, Reuters

Another Davis double fault gives an opening to Watson, who soon leads 0-30. The serving is getting very nervy again. Davis fights back to 30-30, then edges ahead with some brilliant reactions at the net. Watson bounces a shot at her, which hits the top of the net, and the American angles a winner across the court for 40-30. Another thrilling rally follows, before Davis steps up the pace and Watson goes long with a forehand.

Now the Briton has to serve to stay in the match. The next few minutes will be a huge test for her.

Watson looks tentative on serve, and a brilliant forehand winner gives Davis a 15-30 lead. The Briton then mis-hits a backhand to give her opponent two break points - saving the first on her second serve as Davis balloons a forehand wide. Watson nets again with a first serve... and mis-hits when Davis returns her second. Oh dear.

Frustration for Watson, who drops her racket to the ground in annoyance. That was not the service game of a player who expects to win this match. And if she carries on serving like that, she won't.

Image source, Getty Images

Big trouble for Serbia's seventh seed Ana Ivanovic who trails Dominika Cibulkova 4-1 in the deciding set. Kei Nishikori is looking more secure - the Japanese now leads the talented Frenchman Benoit Paire 4-6 6-3 6-3.

British Davis Cup player Colin Fleming:  "It's certainly discombobulated Lauren Davis. I think she just got nervous there."

Word of the day there, Colin. There's full commentary on the BBC Sport website - click the 'live coverage' icon at the top of this page.

A double fault gets Davis off to a nervy start, and a two-handed passing shot from Watson makes it 0-30. How she needs to make the most of this chance...

Davis serves long. Her second serve... is into the net. A double fault gives Watson three break points.

Again, Davis serves into the net... twice! Astonishing - three double faults from the American, at the worst possible time, gift the game to Watson, who is now serving for the second set.

Mark:  This is a really winnable match for Heather and she is conspiring to lose it currently. Come on Watson!

A good cross-court winner from Watson to start, and she soon leads 30-0. A terrific down-the-line backhand winner from Davis gives the Briton something to think about. Davis then drags her opponent across court and misses a good forehand chance. Watson, playing well behind the baseline, cannot drive home the advantage, though, ballooning a forehand as Davis pulls back to deuce. No margin for error here...

It's Davis who blinks first, with two errors that allow Watson to hold. The Briton hangs on.

Piers Newbery
BBC Sport

There is plenty of support for Watson as she struggles to find her game, possibly the lasting effect of her high-profile encounter with Serena Williams at Wimbledon. The Briton is certainly a more recognisable face than Davis, even to American fans, and apparently a big draw for an outside court.