Piers Newbery
BBC Sport at Flushing Meadows

It doesn't exactly bode well for the weather as he's due to play later, but British number three Aljaz Bedene is among the spectators on Ashe for this one, clapping politely as Lajovic moves ahead. Otherwise it's a battle for seats at every changeover, not many spares around now as more and more spectators forsake the sodden food court for some actual tennis. So far, we're on for back-to-back shocks...

A ridiculous net cord loops the ball over Nadal at the net and drops it right on the baseline to give Dusan Lajovic break point.

Nadal slots an ace down the middle to save.

And there is another to wrap up the escape.

Image source, EPA

Dusan Lajovic stands his ground on a line call at 40-15 down and the video review backs his stubborness.

He gets a free pass back into a game that seemed over.

Two netcords in one rally, the second transforming his fierce forehand into a delicate dropper in an instant gives him 40-30.

Nadal clambers into an enormous mid-court forehand to try and kill the game at a second attempt, but pumps wide...

Deuce.

These two have only ever stared across the net at each other once in a competitive match. And Rafael Nadal won. The Spaniard dropped just four games in their fourth-round match at Roland Garros in 2014.

Dusan Lajovic looks well up for this, striding from side to side and serving big.

Rafael Nadal seems to be pondering if he left the gas on or the front door unlocked.

A little lack of focus, a big lack of accuracy and the game is gone to love.

Image source, Getty Images

Leon Smith
Great Britain Davis Cup captain on BBC Radio 5 live sports extra

Lajovic just shifted his tactics at that 30-40 point after losing the two previous points. He started with a couple of slice backhands just to give a different look for Nadal. It was a smart play and it is a really good start for him.

David Law
Radio 5 live sports extra commentator at Flushing Meadows

Image source, BBC Sport

Two-time Grand Slam doubles champion Andrea Hlavackova and GB Davis Cup captain Leon Smith in the 5 live sports extra commentary box.

After a dominant opening game, the Rafa express has come off the tracks in service game number two.

The tee-off lacked the pep and precision, allowing Dusan Lajovic to get into game, and wayward groundstrokes handed over the break.

Now then. Dusan Lajovic with 0-30 and suddenly Rafael Nadal looks a little fidgety as he fields the Serbian's groundstrokes on the baseline.

A forehand screwed between the tramlines and the world number one has three break points to save...

Image source, Reuters

Leon Smith
Great Britain Davis Cup captain on BBC Radio 5 live sports extra

Lajovic has got a big forehand, which you would expect from a clay-court player, he generates a lot of ball speed, which he is doing.

Of course he will be nervous playing Nadal on Ashe but he will be feeling much better after getting that game under his belt.

He's been around quite a while and played many Slams so he is used to playing the big names.

From Christopher Clarey of the New York Times...

Dusan Lajovic has a slugging forehand - a short, compact little punch of a shot - but the party really starts on the backhand.

A long, leisurely one-handed roll of a stroke.

The combination, topped off with a corking serve winner, is enough to hold the opening game with some to spare.

Image source, Getty Images

Leon Smith
Great Britain Davis Cup captain on Radio 5 live

Who is the favourite out of Roger Federer and Rafa Nadal from the outset? It depends on how they are feeling physically. There has been talk about Roger's back and how will that react, especially over five sets.

Nadal, is there some hints around his knee? And he's had a couple of losses against Shapovalov and Kyrgios.

I think Roger, if he is fit, has played the better tennis on this surface. It's tough to call... but it might not be them.

It is unbelievable they have not played against each other here and it would be pretty special if they met under the lights in the semi-final.

But I think it is still unpredictable because of the aches and pain.

Rafael Nadal doesn't do looseners.

His serve is already fizzing like sherbet.

He pushes the speed gun north of 120mph a couple of times on the way to a love hold.

Ominous for Dusan Lajovic opposite.

Image source, AFP

Bottles lined up, shirt shoulders plucked, nose tweaked, balls bounced and finally, we are ready to start.

John McEnerney‏: Rafa should breeze into week two and then we'll see what he has left in the tank after a tough season. Hard courts on those old knees!

Image source, Getty Images

Leon Smith
Great Britain Davis Cup captain on BBC Radio 5 live sports extra

I can't believe we have got rain jackets on. It is significant rain out there. I'm surprised the organisers are not cancelling some of the matches already. I think they will start to pull some of the last scheduled matches.

David Law
Radio 5 live sports extra commentator at Flushing Meadows

Image source, BBC Sport

Unsurprisingly people are flooding into the only court with a roof - it's currently due to rain until 3am US time. This weather brings back memories of my first US Open in 2003 when the second week had no play for four straight days, and we had daily press conferences where they tried to explain why they don't cover the courts. They still don't cover the courts.

Image source, BBC Sport

Image source, Getty Images

Dusan Lajovic's 2017 has been a lot less stellar than Rafael Nadal's so far.

He has 14 wins to 15 losses with last-eight finishes in low-key events in Istanbul and Kitzbuehel his best tournament runs.

However, the 27-year-old gave Roger Federer a mini-scare at Wimbledon this year, taking the first two games to move 2-0 up in the opening set before normal Swiss service was restored.

Image source, Getty Images

A quick check on the pre-tournament photo ops shows Rafael Nadal indulging in some wiff-waff badminton against Venus Williams at an upscale New York Hotel.

Those slip-on velvet numbers would help him as he lunges for the drop-shots.

No report on a victor, but it seems like badminton was the real winner.

Image source, Getty

Image source, Getty Images