Murray finishes off that point with a tugged backhand winner for 30-15 and outlasts Kuznetsov to seal another hold. Murray is bullying him out there...

That's a dreamy forehand pass from Murray, after a bit of a punch-up, to make it 30-30. But Kuznetsov does well on the next point, finishing it with a cute stop-volley. Fine forehand down the line from the Russian for 40-30 and he gets on the board in the second set with a forehand down the middle.

Tom Arnold:, external If Andy keeps up this onslaught, he'll have this in the bag before #Doctorwho starts. Bonus!

Charles Nurick:, external Solid set for Murray but want to see him keep this intensity. Kuznetsov has shown glimpses of what he's capable of.

Angus urquhart:, external #andymurray making light work of his match today. Very disappointing and unMurray like. Maybe time for some cramp?

Murray has a bit of a grumble at himself after losing the first point of the game -"too slow", apparently - before Kuznetsov puts away a forehand winner. What a shot that is by Murray, backtracking, making room before sending down a bodacious forehand that his rival is unable to deal with. Kuznetsov works another break point courtesy of some fearsome ground-strokes but blows it, yanking a backhand into the net. Murray holds again, that's a kick in the guts for the Russian.

Meanwhile, top seed Novak Djokovic is also on track for the US Open fourth round as he takes the first set against American Sam Querrey. The Serb won 6-3.

Russell Fuller
BBC tennis correspondent at Flushing Meadows

"Murray had to save three break points but that was a commanding first set performance. He took it 6-1 & is really attacking Kuznetsov's second serve."

Piers Newbery
BBC Sport at Flushing Meadows

"The Armstrong crowd get their first chance to whoop and, in some places, holler when Murray wins a ding-dong rally at the net, but it's been fairly low key on a stiflingly humid afternoon. The usual refreshment-based bedlam ensues at the end of the set."

Kuznetsov looking all at sea out there and he falls 15-40 behind. Nice forehand winner to keep him in it but Murray kills the game with a vicious forehand pass. It's not getting any easier for the Russian in set two.

Image source, Getty Images

Murray's coach Amelie Mauresmo, in charge of the Briton for a second Grand Slam, watches on - and she must be delighted with what she is seeing.

Miles Maclagan
Former coach to Andy Murray on BBC Radio 5 live Sports Extra

"Murray will be very satisfied. It is exactly the way he would have wanted it go. He has played some good tennis and has contained everything thrown at him. I would give him eight out of 10."

Great point - Murray and Kuznetsov engage in more cutesy stuff at the net, the Russian throws up a lob, Murray gets a lucky net cord before putting away an awkward backhand volley, or at least that's what I think it was. Murray sends down a booming first serve for 40-30 and set point, which he converts. Murray looking like a US Open champion in that set, although his rival looks somewhat overawed.

Murray wins a spot of tit-for-tat at the net and moves into a 0-30 lead. Kuznetsov getting the equivalent of an old-fashioned twist of the ear and a boot up the backside from Murray in that game, that's a break to 15.

The odd tweet or text, or perhaps even a letter, pertaining to the match in question might be nice. You can talk about whatever you like really, that's the beauty of living in a democratic society, but we'd prefer it to be about tennis. Kuznetsov finding some form and here he is forcing another break point, sending Murray scampering with a wicked forehand before killing off the point. But Kuznetsov blows his chances, ballooning a forehand long, and Murray holds again.

Miles Maclagan
Former coach to Andy Murray on BBC Radio 5 live Sports Extra

"I think Murray is playing the best tactical tennis of his career these days. When he was beating everyone easily it was because he was that much better than them, now he has to think about it more."

Kuznetsov looking frail against the mighty hitting of Murray at the moment. It's a lesson in playing tennis with the big boys - Murray is a serious unit nowadays. Murray levels things at deuce behind a whipped forehand before Kuznetsov nicks the advantage with a backhand volley. Murray is all over the Russian's second serve. He was almost on the service line when he hit that return, which made things deuce again. But Kuznetsov chalks one up, at last.

Over on Arthur Ashe Stadium, Serbia's top seed Novak Djokovic is looking comfortable in the early stages of his third-round match against America's Sam Querrey, taking a 2-0 lead with an early break.

Murray fizzes a forehand winner past the stationary Kuznetsov for 15-15 but the Russian forces two break points with a crackerjack forehand winner down the line. Murray saves the first with a well-directed first serve before levelling things courtesy of a hammer of Thor, wrong-footing backhand. Murray rides out the storm, those legs of his look good as new.

Miles Maclagan
Former coach to Andy Murray on BBC Radio 5 live Sports Extra

Image source, Getty Images

"Top quality returning from Murray. It is a nightmare start for Kuznetsov to go behind against a top player."

Kuznetsov has got a pretty loose delivery and it's misfiring in this first service game. A couple of iffy first serves and Murray is all over him like a rash, racing into a 15-40 lead in the game. Kuznetsov can't handle that meaty Murray return, dinking a timid backhand into the net, and that's a break.

Kuznetsov takes the opening point of the match before Murray has a bit of trouble with his toss. Kuznetsov should make it 0-30 but Murray scrambles his way level before the Russian fires into the net with a forehand. Murray makes the most of a fine second serve for 40-15 before sealing the game with an out-swinging ace.