In the regular season, the Owls finished 19 points better off than their hosts, who managed to climb back into the top six on the final day, thanks to the Owls' beating of Derby County.
Match preview
Peterborough United will head into the playoffs on somewhat of a high, having snuck back into sixth place on the final day of the regular League One season after previously dropping out.
Following Darren Ferguson's return to the club as manager at the beginning of the new Year, the Posh have collected 42 points from their remaining 22 games in England's third tier, and they successfully climbed into the top six with a positive run of four wins from a five-match span across March and April.
After those results fired them up to fifth place with five games to go, Ferguson's men were unable to sustain the fine form and quickly dropped back out of pole position in the playoff race as 2-0 and 3-0 defeats to Cambridge United and Ipswich Town respectively followed, either side of a victory over Accrington Stanley, before a disappointing draw with Bristol Rovers left them two points behind sixth-placed Derby County heading into the final round of fixtures on Sunday.
With the Rams also boasting the slightly better goal difference ahead of their meeting with Sheffield Wednesday, the Posh required a favour from the Owls and a victory of their own in a tough test away at fourth-placed Barnsley, but they would defy the odds and sneak back into the final playoff place, as Derby fell to a 1-0 defeat at Hillsborough while Peterborough enjoyed a much more successful trip to South Yorkshire with Jonson Clarke-Harris and Jack Taylor on the scoresheet in a 2-0 triumph.
Now still having a chance of making an immediate return to the Championship following their relegation last term, the Posh will hope to carry momentum from that dramatic final-day success into Friday and make the most of home advantage to go ahead in their tricky semi-final tie.
They take on a Sheffield Wednesday side who had their sights set on the automatic promotion places throughout the campaign and occupied a spot in the top two until the beginning of April thanks to a 23-game league unbeaten run between October and mid-March.
The Owls would eventually be overtaken by both Plymouth Argyle and Ipswich Town, as that streak was followed by a six-game unbeaten run in which they managed just four points, leaving them chasing for the final six outings of the regular season.
A 3-0 beating of Accrington Stanley was then followed by a harmful 3-2 defeat away at Burton Albion, before four straight wins were not enough to narrow the deficit to the relentless top two, as they put up triumphs over Bristol Rovers, Exeter City and Shrewsbury Town before beating Derby County 1-0 on the final day on Sunday courtesy of Michael Smith's first-half penalty.
With Plymouth and Ipswich not letting up, Darren Moore's side remained confined to a third-placed finish, despite picking up an eye-catching tally of 96 points, more than any side who have gone up from England's third tier automatically in second spot since Blackburn Rovers in the 2017-18 term.
While they will feel somewhat disappointed with the strong season not rewarded with an automatic climb back to the Championship, having managed 28 triumphs over the course of the campaign, the Owls have at least rebuilt plenty of momentum ahead of the playoffs with their four straight wins and will hope to build on that on Friday with a positive result in the away leg before welcoming Peterborough to Hillsborough next week.
Peterborough United League One form:
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Sheffield Wednesday League One form:
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Team News
Following their final-day triumph under pressure away at Barnsley on Sunday, Darren Ferguson should deploy an unchanged Peterborough United starting XI for the first leg of their playoff semi-final tie, in their preferred 4-2-3-1 setup, with Jonson Clarke-Harris again bound to lead the line after moving joint-top of the league's scoring charts with his 26th of the season at Oakwell.
There is plenty of quality in the supporting trio behind the talismanic forward too, with Ephron Mason-Clark having contributed nine goals and eight assists in League One from the left flank, while Jack Taylor has also starred in a central role with eight goals and five assists of his own in the third tier.
Behind them, Hector Kyprianou will again join Ollie Norburn in the engine room, while centre-backs Ronnie Edwards and Frankie Kent have been key men throughout the season and will continue their partnership at the heart of the back four.
Darren Moore has recently seen his defensive options boosted by the return of Michael Ihiekwe from a long-term injury, while midfielder George Byers remains sidelined alongside forward Mallik Wilks.
Ihiekwe will fight with the likes of Aden Flint, Jaden Brown and Dominic Iorfa for places in the back three, with Liam Palmer and Marvin Johnson set to continue in wing-back roles, while Will Vaulks will play an important role alongside star man Barry Bannan in the midfield.
Michael Smith will lead the line, after hitting his 20th league goal of the season in the win over Derby, with Josh Windass also likely to come back in from the outset, while Lee Gregory remains a doubt after missing Sunday's contest.
Peterborough United possible starting lineup:
Norris; Ward, Kent, Edwards, Burrows; Norburn, Kyprianou; Poku, Taylor, Mason-Clark; Clarke-Harris
Sheffield Wednesday possible starting lineup:
Dawson; Iorfa, Flint, Ihiekwe; Palmer, Bannan, Vaulks, Johnson; Windass; Smith, Paterson