Nabil Hassan
BBC Sport at The County Ground

"'It's a sell out.'

"Not something Swindon Town have been able to say much this season, but tonight nearly 14,000 will pack into the County Ground to see the Robins take on Sheffield United.

"The atmosphere outside was one of optimism from the home supporters, and despite their manager's mind games, they see their side as favourites going into this game.

"Blue skies and a light breeze await United's fans in Wiltshire, and with their woeful play-off history in mind, they have a massive task to turn things around here."

Image source, Getty Images

Preston became the first club to book their place in the League One play-off final after completing a 4-0 aggregate win over Chesterfield yesterday.

Jermaine Beckford scored twice in a 3-0 victory at Deepdale. The first, a turn and volley inside the box, was decent enough. His second, a shot from the halfway line, was a bit special.

In League Two, Stevenage and Southend drew 1-1 in the first leg of their semi-final, leaving that one finely poised ahead of Thursday's second leg at Roots Hall.

BBC Sport

Image source, Getty Images

So far, Preston North End are the only club to have confirmed their place in a Wembley play-off final later this month. Either Swindon Town or Sheffield United will join them this evening.

Remember, you can follow every Football League play-off match on the BBC Sport website. We'll be providing a live text commentary of every game, including the finals on 23-25 May.

Swindon finished fourth in the League One table at the end of the regular season, having been top over the Christmas period.

They won 23, drew 10 and lost 13 of their 46 games.

Sheffield United ended up fifth - a position they held since February - with 19 wins, 14 draws and 13 defeats.

The Blades beat Town 2-0 at home in January but were smashed 5-2 in the away fixture in September.

Image source, Getty Images/BBC

Image source, Getty Images

Swindon attempted to reach the Championship in the 2012-13 season but lost in an agonising penalty shoot-out at the semi-final stage to Brentford.

It was to be manager Kevin MacDonald's final game in charge, and the reins were handed to then assistant boss Mark Cooper.

Sheffield United's play-off record is, well, dismal. Let's look at the history books.

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1988: Sheffield United were beaten in a two-legged relegation play-off against Bristol City, which dumped them out of Division Two - or in current money League One.

1997: Lost to 1-0 Crystal Palace in Division One play-off final.

1998: Went out at the semi-final stage to Sunderland.

2003: Beaten by Wolverhampton Wanderers in the play-off final.

2009: Lost 1-0 to Burnley in the Championship play-off final.

2012: Beaten on penalties in the League One final by Huddersfield.

2013: Lost to Yeovil in the semi-finals.

Image source, Getty Images/BBC

Andy Williams came on for the final 14 minutes of Swindon's first-leg win at Bramall Lane, but he won't be available to be called upon tonight. Will the hosts miss their top scorer?

Swindon Town: Foderingham, Stephens, N. Thompson, Turnbull, Byrne, Kasim, Luongo, Gladwin, Ricketts, Hylton, Smith.

Subs: T. Belford, Barthram, Branco, Marshall, Rodgers, Randall, Obika.

Sheffield United: Howard, Alcock, Harris, Basham, Flynn, Murphy, McNulty, Done, Coutts, McEveley, Freeman.

Subs: Turner, Doyle, Davies, McGahey, Adams, Davies, Holt.

Swindon manager Mark Cooper names the same starting XI from the first leg but Andy Williams and John Swift drop off the bench (not literally).

Williams has a groin issue while Swift has a calf problem, so Raphael Rossi Branco and Will Randall are called up in their place.

Sheffield United make three changes to the starting line-up.

Craig Alcock, Marc McNulty and Matt Done are in. Steven Davies, Jason Holt and John Brayford are out.

It was all going swimmingly for Sheffield United in Thursday's first leg at Bramall Lane...

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Kieron Freeman's low drive put the Blades ahead on 19 minutes, and Swindon's Ben Gladwin missed from the penalty spot to leave the hosts 1-0 up at half-time.

But a bullet header from on-loan Wolves man Sam Ricketts brought Town level before the aforementioned Nathan Byrne popped up with the winner in added time.

The 1,179 travelling fans went bananas, as the 20,890 home fans gently wept.

I wonder how many nightmares Sheffield United fans have had about this man in the last four days.....

Image source, Getty Images

Nathan Byrne's strike last Thursday has given Swindon the advantage going into tonight's League One play-off semi-final second leg.

But, as cliche-ridden football managers up and down the land will persist in telling you: The play-offs are a lottery, there's still 90 minutes to go, and it's still all to play for.