The Blades travel to Yeovil Town knowing a draw will be enough to book a trip to Wembley on May 19.
For Porter, that would represent another step towards ending what has been a frustrating season that he feels only really got started when Chris Morgan came in to replace Danny Wilson midway through last month.
Since then, the striker has started all six games – in stark contrast to the rest of the season, when he made the starting line-up just nine times in league fixtures and even had a spell out on loan with Shrewsbury Town.
On the back of helping the Blades to a 1-0 first-leg victory on Friday night, Porter said: “All I can do is give my all. Since Chris came in and he has been picking me, I feel a lot happier now.
“I do feel to be playing better and I feel more confident. I feel there is someone here now who has confidence in me.
“That is a big difference to me personally. If you are not getting picked then you feel that the world is against you.
“I did feel, at times, that even if I played well then I would not be picked.
“That weighs you down a little bit. But now I go out and feel confident in myself.”
Wilson’s dismissal in the wake of the 2-0 home defeat to Crawley Town on April 9 was one of the more surprising moves of the 2012-13 season, but the subsequent appointment of Morgan until the end of the season proved a popular one with the squad.
Porter added: “Chris Morgan has massive respect right through the club, from the fans to the team.
“Everyone wants to do well for themselves, but also him as well. He is so passionate about the game and about Sheffield United. That rubs off on the players.
“We are going to need plenty of that in the play-offs.”
United will travel to Huish Park for the 1.30pm kick-off in confident mood following the manner of Friday’s first-leg triumph.
The Yorkshire club can also look back on a 1-0 victory over the Glovers in Somerset earlier in the season.
He added: “Yeovil is a tough place to go, but we have already won there this season. They have been doing well and have a good home record, but this is the play-offs and we will go there to give our all. We can’t go down there and try to soak up the pressure. If we sit back, we will probably concede. So, the balance has to be right and we have to go looking to score.”
Further encouragement comes from United having already kept 22 clean sheets this season, a club record.
Porter added: “The defence has a great record. We have maybe not scored as many goals this season, but we have kept a lot of clean sheets.
“That starts with the front lads, as we have to drop back and fill in. The midfield plays a bit deeper and that makes us more solid.
“It means we don’t create as many chances, but that has been our motto all season. That is why we have so many clean sheets, meaning often we only need one goal to win it.
“Hopefully, we can keep another at Yeovil as that will mean we go through.”
On the balance of the tie, Porter, a 2011 signing from Derby, said: “We are halfway there after a good result. I thought we deserved to win and could maybe have had a couple more goals.
”This season has been frustrating on a few levels, but it could end in a really special way.
“People thought that we might get automatic promotion. I thought we had the team and squad to do that ,but it was not to be. Now, we need to take that frustration out by winning the play-offs. Everyone says the play-offs is the best way to go up and I am sure that is the case.”
Last six games: Yeovil Town WWLWLL, Sheffield United WDLLDW.
Last time: Yeovil Town 0 Sheffield United 1; September 22, 2012; League One.
Referee: P Gibbs (West Midlands).
Brentford captain Kevin O’Connor’s late penalty earned them a 1-1 draw in their semi-final first leg at Swindon, cancelling out Massimo Luongo’s 70th minute-opener.