On Saturday afternoon Sunderland fans caught a glimpse of what Grant Leadbitter can offer this season - but what else can they expect from the midfielder?
Leadbitter set up the only goal of the game against AFC Wimbledon at the Stadium of Light, when his cross-field pass picked out Aiden McGeady to score the winner.
Black Cats supports know Leadbitter, 33, well, after the midfielder came through the club's academy over a decade ago.
But what qualities will he bring to this Sunderland side and why was he allowed to leave Boro - where he was the club's captain and a popular figure?
We caught up with Middlesbrough fan and editor of Boro fanzine Fly Me To The Moon, Rob Nichols, to get the inside track on Sunderland's new signing.
How is Leadbitter viewed among Boro fans?
"Grant is greatly admired and hugely respected for playing a real captain's innings for Boro and leading us through some stormy seas and at one point into the Premier.
"That promotion season he played through the pain barrier putting his team first and postponing an operation which led to him missing most of our top flight stay.
"That was typical of the man and why he will always have a place in our hearts at the Riverside."
Why didn't he play much under Tony Pulis this season?
"Under Aitor Karanka we played Leadbitter and Adam Clayton as dual pivots in midfield but after the exit of the Basque boss there has been a change of plan and it has been a case of selecting either Grant or Adam Clayton for that holding midfield position.
"Last season it was initially Grant who held sway but Clayton was brought back in later on and the younger man has cemented his place in the side.
"With the recent signing of the highly-experienced John Obi Mikel we had that position covered in depth so the time was right not to stand in Grant's way of getting first team games."
Do you think he could still do a good job in League One and, if Sunderland get promoted, the Championship?
"Grant Leadbitter will be a superb signing for Sunderland.
"He played superbly skippering the team to a Carabao Cup quarter final this season and doesn't look to have lost any of the fight, bite but also passing ability.
"He looks to still have plenty of miles left in his engine."
Sunderland fans know all about the midfielder following his time at the Stadium of Light, but what are his best qualities and what will he bring to the side?
"He is a cool operator in midfield.
"Not easily ruffled, never intimidated, Grant Leadbitter leads by example on the pitch but demands all around give absolutely 100 per cent for the cause. That probably extends to fans as well as team mates.
"Apart from his work rate and huge experience, Grant has an eye for a pass and still has the legs to get on the end of one himself.
"He does the simple things well, something that is always appreciated from the stands.
"One of the all time great penalty kings at Boro, he rarely misses his mark from the spot."
Were you disappointed to see him leave Boro?
"Boro fans are delighted to see Grant repaid for all his service at Boro with a dream move back to his first club.
"That sentiment is universal among Boro fans and speaks volumes because I can honestly say I have never known of any player moving on from Boro to our rivals with anyone's, never mind everyone's, blessing.
"But Grant is a unique personality he took Boro to his heart and Boro fans took him to our hearts too and we absolutely wish him all the best.
"He will be given an ovation when and if we meet again but then he will no doubt crunch into a tackle.
"We would not expect anything less from a player that wears his heart on his rolled up sleeve and gives everything for his team."