Sunderland's third clash with Portsmouth this season is their biggest yet.
Less than a month since the Checkatrade Trophy final, the two meet with their automatic promotion hopes on the line.
So where will this one be won and lost?
We take a look at the key lessons from the previous games...
McGeady v Thompson will be another epic
Nathan Thompson has established himself as one of the toughest, most consistent right backs in League One.
His first goal in a Pompey shirt came during that Checkatrade Trophy final at Wembley, an excellent run to the back post and a fine header.
It was just one installment in what was a superb contest with Aiden McGeady.
McGeady had been exceptional in the first half and fought back in stunning fashion, leaving Thompson on the floor as he scored an equaliser in the dying moments of the game.
The battle has an even more interesting dynamic on this occasion, with the Irishman playing with a broken bone in his foot.
Speaking on Thursday, Thompson said: "Aiden is probably one of the only players capable in the league who can play with a weakened foot and still get away with it because he’s that good.
"But it is a test that I am looking forward to.
"Wembley was good fun and he is capable of a lot. He’s in the Team of the Year and is better than League One – even he knows that.
"It’ll be an interesting one to see how it goes. It’s strange that he’s come out and said he’s injured because it will certainly play on my mind.
"He is capable of turning the game on a sixpence. He’s got the step over, can move either way and if you don’t get tight then he’ll punish you in that sense.
"As the game went on at Wembley, I felt I got closer and we got on top of the ball, which negates his potential.
"We did a job on him at Fratton Park. We got close to him and got bodies around him.
"He’s able to create a bit of room and they rely on him a little bit to create opportunities for players up front.
"It's important we do a job on him again."
It will be another fascinating and decisive clash.
Jackett will surely go with Oli Hawkins
Kenny Jackett has admitted that with Omar Bogle injured, he has a straight choice between James Vaughan and Oli Hawkins.
Though some would feel a Vaughan goal at his old club would be somewhat inevitable, the away side will surely go with Hawkins.
After Glenn Loovens saw red at Fratton Park in December he was outstanding, constantly winning headers and freeing dangerous wingers into space.
At Wembley he came off the bench to help turn the tide of the game, his hold-up play getting Portsmouth up the pitch and allowing them to build pressure. Brett Pitman, perviously peripheral as the number ten, was suddenly getting plenty sight of goal.
Given that Sunderland's defensive physicality is a key frailty, this battle will be vital.
Midfield battle will be key and Sunderland can win it
That memorable final was the archetypal game of two halves.
Sunderland completely controlled the first half before coming under major pressure in the second.
Still, they will take great confidence from that opening 45 when Grant Leadbitter and Lee Cattermole completely controlled the tempo.
Ben Close has been in top form in the Portsmouth midfield but had little joy until the latter stages.
Jack Ross must be tempted to rekindle that partnership for such a high-pressure game.
Cutting off Clarke is vital
When Portsmouth's Wembley goal came it was little surprise that Matt Clarke started the move, carrying the ball out from the back all the way to the edge of the box.
A superb defender, he has also proven himself to be crucial for Portsmouth with his distribution.
Sunderland simply have to cut him off far better at the Stadium of Light.
Pompey have been in exceptional form this season but Clarke's centre-back partner Christian Burgess remains a stand-in for the injured Jack Whatmough and is a player they can target.
A big decision to make out wide
With Pitman starring in a new role behind the striker, Gareth Evans has found his gametime reduced.
Ronan Curtis has had an exceptional campaign but Sunderland had the measure of him in the Checkatrade Trophy final.
He was replaced early in the second half by Gareth Evans who alongside Hawkins, helped turn the tide. He had the beating of Luke O'Nien in the air and caused big problems for Sunderland as he drifted into dangerous areas from the wing.
Evans has not always been so effective in that role and indeed was replaced by Curtis at half-time as Jackett guided his team to a comeback win against Coventry City.
It is a tricky decision for the Pompey boss.
Wyke can be a (relatively) secret weapon
One thing Sunderland have not been able to call upon in either game against Portsmouth is a powerful centre-forward.
Will Grigg started brightly in the last game between the two but was physically in poor condition after suffering an ankle problem.
Charlie Wyke did well after coming off the bench but since then has taken his form to the next level.
His build-up play has been excellent and his aerial ability impressive.
That could be key in giving Sunderland a different dimension, particularly during difficult spells when they need an out ball.