The Riverside Stadium stages another encounter of seminal importance for both sides this evening (8pm), with three precious Premier League survival points up for grabs.
This is in contrast to March 18 when both were battling for automatic promotion from the Championship.
A dramatic denouement in the Spring saw Boro substitute David Nugent head home a stoppage-time winner for the Teessiders in a 1-0 triumph – inflicting a huge psychological blow upon Hull’s top-two quest which they never truly got over, having to go up via the play-offs.
Eight-and-a-half months on and Phelan is calling on the second-from-bottom Tigers to maintain focus for the game’s entirety as they seek to leapfrog Boro in the table with victory.
The Hull chief said: “Concentration is always a massive thing. You also cannot afford to waste energy trying to play the game before you get on the field.
“We know what we have to do and we will be prepared for the game. We just have to make sure the players are not overawed by the game or take it too seriously to their detriment. You cannot get nervous.
“You have to be composed, compact and accept the challenge ahead.
“It does not matter if it is Middlesbrough or Liverpool, we have to make sure we do what we can to influence the game.
“We lost the game (in March) through a lack of concentration in the final part of the game.
“Until that point, it was job done. We had played well as the away team, we were there and then one lapse of concentration costs us the points.
“That happened to us at Watford as well, so these are building blocks and we have to use these experiences to make sure we are not caught out again.”
Both goalkeepers are likely to prove pivotal figures amid the Riverside cauldron this evening, with first-choice Tigers’ custodian David Marshall relishing his contest with a world-renowned name in home goalkeeper and one-time former Barcelona No 1 Victor Valdes.
Marshall admits that the 34-year-old is somebody who he has looked up to during his own career, right from the moment they lined up on opposing sides in a fateful Uefa Cup tie in March, 2004 between Celtic and Barca.
Then still a teenager, Marshall came on at the interval in the first leg at Celtic Park following the dismissal of Hoops goalkeeper Rab Douglas and managed to keep a clean sheet in a 1-0 home win – before repeating that feat in the second leg at the Nou Camp as Celtic claimed a famous aggregate triumph.
Marshall, who also lined up against Valdes in two Champions League matches in 2004-05, said: “Celtic were my team growing up and the first leg was surreal really.
“I was just warming up at half-time and the goalie coach came running out and I think they had two guys sent off and we had the goalie sent off.
“Valdes came through the ranks at Barcelona and I came through at Celtic and he was a goalkeeper I looked up to, coming through. He obviously went on to to become an outstanding goalkeeper.
“In the last couple of years, he has had a bad injury and chose to leave Barca. But when he was there, he won everything. I have his shirt from the first leg (in 2003-04) when he wore it and I kept my one from the second leg, which we won. It is in the garage and, as I have just moved house, everything is boxed up.
“But once I have finished playing, I will get it up in the house.
“When he left Barca, he picked up that injury three or four months before he left and it set him back that way.
“But it does not surprise me that he’s still going strong. At the top level, goalkeepers seem to go on longer and longer now and it is no surprise he is doing well in the Premier League.”
On tonight’s encounter, he added: “There is only a point between ourselves and Middlesbrough and it is a big game and you do not want that gap to widen and, hopefully, we can overtake them.”
Hull are one of a number of sides reportedly keen on landing Boro striker Jordan Rhodes in January.
Last six games: Middlesbrough LDWDLD, Hull City WLWLDD.
Referee: M Dean (Wirral).
Last time: Middlesbrough 1 Hull City 0, March 18, 2016; Championship.