This is close. Very close. At 30-30 the players battle it out from the baseline, crunching groundstroke after crunching groundstroke... Kerber gambles like a high roller in a Vegas casino and is rewarded - a forehand down the line grazing the paint. A celebratory roar from the German. Could that be the turning point? She holds, she's ahead once again. 

Jeff Tarango
Former professional tennis player on 5 live sports extra

There was a couple of bad decision from Pliskova there.

Image source, Getty Images

Opening point to Kerber. Interesting. But the German swings wildly at a forehand on the next point and flaps her arms in exacerbation. From 15-15 to 30-30. Tense. Nervy. Cool heads needed. 

Pliskova's feet dancing to a different beat on the next point, stuck in treacle, causing her to drag a forehand wide. Break point Kerber. The Czech thinking of what could lie ahead perhaps, thinking of a first Grand Slam win... she's no longer hitting with freedom, a tension-filled backhand into the tramlines and Kerber breaks. This is close. 

Jeff Tarango
Former professional tennis player on 5 live sports extra

This isn't near over. There is a lot of tennis to be played.

Image source, Reuters

An ace out wide secures a hold to love for Kerber. The second seed is not out of this contest yet. 

Kerber a shadow of the player she was in the first set. Her mother watches on, concerned, biting her bottom lip. The German making the net look as if it's 10ft tall. Pliskova bossing it now, coolly holding.

Image source, Getty Images

Jeff Tarango
Former professional tennis player on 5 live sports extra

Kerber is mentally disturbed right now.

She is making errors she wouldn't normally make and going for shots she wouldn't normally go for.

Oh my word. Pliskova has acres to aim at, Kerber is out of the point, outmaneuvered, but the Czech slaps a volley into the net. It could have been 15-40, instead it's 30-30. What a chance. The second seed off the hook. Temporarily. 

Kerber still up against it, she has to hold her nerve here, which she does by forcing the game to deuce by saving a break point. 

A second break point for Pliskova, though. Kerber long, long, long. The Czech skips to her chair, she's ahead for the first time in this match, she's broken in the deciding set. 

Image source, Getty Images

Former greats Tracey Austin and Jimmy Connors looking on, watching Pliskova hold to love. Neither player flinching in the early stages of this deciding set. Intriguing, entertaining, you can take your eyes off it. 

Prior to that second set, Kerber had not dropped a set in this tournament. What impact will that have on the German? We are about to find out. 

Of the pair's seven previous matches, two have done the distance with Kerber winning both (in Stanford and Birmingham last year). Does that mean anything? Who knows. 

Kerber begins with a comfortable hold. Nerveless stuff. 

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

This will depend on how Pliskova serves in this deciding set.

Image source, AP

Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra

It is the first set Kerber has lost but Pliskova played very well.

She served well, put the pressure on Kerber's second serve and got a few more unforced errors compared to that first set.

So. Here we are. Pliskova serving for the second set, serving to take this US Open final into a decider. At 15-15, Pliskova taps a forehand towards Kerber, thinking the German had gone long only for the line judges to remain silent. Kerber gobbles up the tame forehand to advance to 15-30, but Pliskova wipes that point from the memory bank. She holds her nerve, wins the next three points to takes us to a third set. 

Image source, Getty Images

Russell Fuller
BBC tennis correspondent on BBC Radio 5 live sports extra

We are certainly seeing tension in the arms of the woman who is soon to be world number one.

Pliskova has the court at her mercy but, on the run, slaps a forehand into the tape. The crowd despairs, she could have leveled at 30-30. Kerber still on the ropes, though... an iffy dropper fails to cross the barrier and we're at deuce. 

The Australian Open champ produces a brilliant backhand winner to ease ahead but follows up with a double fault. Errors from both sides. Advantage. Deuce. Advantage. Kerber holds. Pliskova to serve for the set. 

Signs that Pliskova might not be able to sustain the highs of the last game. A limp backhand drifts wide, allowing Kerber to nip in front at 15-30. But on the next point Pliskova proves she has gravel for guts, upping the ante, increasing the power, hitting a sweet winner into the corner. 30-30. 

Kerber long on a forehand... Pliskova a point away from consolidating the break... and the second seed long again. A clenched first from Pliskova. The second set is nearly hers. 

Image source, Getty Images

Jeff Tarango
Former professional tennis player on 5 live sports extra

Kerber didn't lose that game or the game before.

It was because Pliskova played some great tennis.

Oof! Big hitting from Pliskova, finding a postage stamp of a corner with a forehand which has Kerber rocking. On the next point the German fails to find the target and slaps her racquet onto the court in frustration. The second seed muttering. 

Another crackerjack of a shot from Pliskova, a backhand which kisses the tramline and the Czech has a break point. She races forward... a throw of the dice, a lob, Kerber stranded and the game is Pliskova's! 

The Czech roars, the crowd cheers. A wonderful match unfolding before our eyes.

Image source, AFP