When Manchester United make the trip to Tottenham Hotspur in the quarter-finals of the Carabao Cup on Thursday evening, there is very little to split the teams with the bookmakers.

Both sides are members of the Premier League's old 'Big Six' club and both teams have suffered indifferent seasons so far. United dominated English football for two decades and once had the ability to routinely sign Spurs' best players.

Teddy Sheringham swapped White Hart Lane for Old Trafford in 1997 and went on to win the treble with United. Dimitar Berbatov also made the same move to great success.

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But perhaps the most successful, if not understated, signing United made from the North London club was their move to bring in midfielder Michael Carrick in the summer of 2006.

United paid £18.6million to bring the 25-year-old to Manchester, as Sir Alex Ferguson looked to reel in Jose Mourinho's Chelsea after they had won the two previous Premier League titles.

But the decision to bring in Carrick hadn't convinced United fans they could do that.

One fan from the Independent Manchester United Supporters' Association told BBC Sport at the time: "I cannot understand what is going on. I have not spoken to anybody who, when £18.6m became available, would have spent that on Michael Carrick.

"But people have questioned Sir Alex Ferguson's judgement in the past and finished up with egg on their face and I hope it happens again."

And boy did the doubters end up with egg on their faces.

Carrick inherited the No.16 shirt which had been worn by United's long-serving captain, Roy Keane. Keane had left the club a few months earlier in abrupt fashion after the fallout from his infamous critical assessment of his United teammates on MUTV.

Ferguson knew he would be a success as soon as he saw Carrick's reaction to being handed Keane's iconic shirt number.

"I said to him 'I'm giving you the number 16 jersey' so he was delighted at that," Ferguson said.

"I think that showed great courage because sometimes players are a bit superstitious about things like that but he was keen, and said he would gladly take number 16."

Carrick established an excellent partnership with Paul Scholes in the middle of United's midfield and in his first season at the club, they toppled Mourinho's Chelsea to win United's first Premier League title in four years.

The following year, United won the Premier League again and ended the season as European champions by beating Chelsea in the Champions League final on penalties. Carrick dispatched his spot-kick in Moscow.

Carrick would spend 12 years as United as a player, winning 18 major trophies across spells also playing under David Moyes, Louis van Gaal and Jose Mourinho.

He was named in the 2012/13 Premier League Team of the Year in Ferguson's final season in charge and was also named United's Player of the Year that term.

Carrick didn't score 20 goals a season and isn't spoken about in the same breath as other midfielders from his generation like Scholes, Steven Gerrard and Frank Lampard.

But the reaction to when he called time on his United playing career in 2018 couldn't have made clearer how highly he was thought of in the game.

Man City boss Pep Guardiola described Carrick as 'one of the best holding midfielders I've ever seen in my life'. Scholes said it was like playing alongside a 'Rolls Royce', while former Arsenal manager Arsene Wenger described it as one of his 'biggest regrets' that he never got to manage Carrick.

In fact, Mourinho thought so highly of him that he offered him a place on his United coaching staff and he remained there under the management of Ole Gunnar Solskjaer.

His time at United ended with a spell in interim charge of the club, before he moved on following the arrival of Ralf Rangnick.

Speaking about the end of his 15-year association with United, Carrick said: “My time at this great club will always rank as the best years of my career.

"When I first signed over 15 years ago, I never in my wildest dreams could have imagined winning so many trophies and I will certainly never forget the fantastic memories both as a player and as a member of the coaching team."

Carrick is now manager of Middlesbrough and looking to spearhead their return to the Premier League. It would be a promotion welcomed by every United fan and their trip to Tottenham on Thursday should serve as a reminder of one of the club's finest servants.