Sloane Stephens cranks up the pace of this game when she needs to - thumping a forehand winner down the line.

But she follows up with a double fault. Williams breaks.

A line judge behind Stephens' end is the latest to feel the force of an overcooked Williams return, but the 37-year-old wrestles her way into her opponent's service game with some silky tennis.

Two break points for Venus.

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Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

As soon as Venus starts making more balls, hitting with more pace, it will be like Sloane Stephens is playing a completely different and superior player on the same stage. With the expectation that she is going to win added into that, it could be a difficult change for Stephens to adjust to.

The opening set was over in 24 minutes. The first game in this second set takes 10 minutes on its own, but it's Venus Williams who closes out for a vital hold.

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Pure power from Venus Williams. You could feel the venom in the punchy groundstroke that fends off a Stephens break.

She's stepping into strokes now, full-bodied and deep-hitting, but that's too deep for the seven-time Grand Slam winner. She can't quite close this out. Deuce.

Every time Venus Williams hits a winner, the Ashe crowd stands and applauds.

They've not been on their feet too often so far.

The pressure builds on the Williams serve as she faults and then lets at 30-40, but battles back to deuce.

Now it's Stephens doing the chasing, before the youngster wraps her racquet around a passing backhand to earn another break point.

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David Law
Radio 5 live sports extra commentator at Flushing Meadows

This is actually quite awkward to watch at the moment. Venus looks like she is trying to find her belief in herself once again.

Right then, what sort of response can Venus Williams muster in this second set?

She opts for a drop shot, but Stephens sprints her way to meet the dying fuzz and lofts over the stranded, outstretched veteran, watching on as it falls suddenly to clip the baseline. Magnificent.

Williams recovers to 15-30. But a double fault hands Stephens two break point opportunities.

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Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

Sloane Stephens hit only six winners, got one double fault, but she didn't really need to do much else to win that set.

Stephens had to keep her composure and did so admirably, but Venus has to take the initiative at the start of this second set because otherwise the match could get away from her fast.

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Sloane Stephens is serving well without really having to hit third or fourth gear so far.

She slices a second serve out wide and then gets Venus scuttling back the opposite way, before closing in on the net to hammer down a smart volley.

Three set points. She only needs one.

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There's great depth to the Stephens return at the minute. Williams can't deal with it from the baseline as it bounces up towards her midriff.

And that's a double break for Stephens. After just 22 minutes.

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A foot injury meant Sloane Stephens couldn't walk earlier this year, right now she looks to be running full pelt towards her first ever Grand Slam final.

She winds up a two-handed backhand and watches on without any flicker of emotion as it skips on past Venus. A sloppy stroke from mid-court makes it 0-30.

What can Williams do to stop the rot?

The click of cameras clunks away behind Stephens as she's papped mid-serve. It doesn't faze the world number 83. She cruises to a 40-15 lead.

Williams calls for her first challenge as a forehand drifts long. And she's spot on. A wry smile. She's not impressed.

But that only delays the inevitable hold for Stephens.

Jeff Tarango
Former professional tennis player on 5 live sports extra at Flushing Meadows

You can't say sluggish, but Venus is definitely not spry. She is still getting moving after that two-and-a-quarter hour match against Petra Kvitova earlier this week.

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And Stephens takes the break.

Another gift from Venus, who rattles the tape with an awkward forehand.

I wonder what's running through Venus Williams' mind as she settles into her courtside chair for a moment's pause? A last shot at an eighth Grand Slam?

Maybe.

She fizzes down a first serve and crunches a forehand from shoulder height to extend her lead in this service game to 30-0. But Stephens, gliding across the Ashe surface, battles back to square thing up before Venus finds the net. Break point for the 24-year-old.

Russell Fuller
BBC tennis correspondent at Flushing Meadows

Monica Seles is here and being introduced to the crowd on the jumbotron screen. It is quite nice how they show celebrities up there but intersperse it with shots of ordinary folk like me as well.

Cat Archer
BBC Radio 5 live at Flushing Meadows

Kevin Anderson's dog has her own accreditation.

Lady Kady came to see us in the commentary box.

Stephens closes out. A powerful serving display when it mattered from the pink-clad American. Another hold.