Middlesbrough boss Warnock, 71, will take charge of his 1,500th Football League game against Barnsley at the Riverside on Saturday after recovering from coronavirus.

Warnock, bidding for a record-extending ninth Football League promotion, embarked on his first season as manager at Gainsborough Trinity 40 years ago and Blackwell has been alongside him most of the way.

Warnock, second right, celebrates with his Plymouth players after sealing his fourth promotion in the play-off final at Wembley in 1996 (David Cheskin/PA)

"We've been very lucky," Blackwell told the PA news agency. "Every other year, near enough, we've been involved in a promotion or a cup run or the play-offs.

"There's so many good things that we've had. We're both blessed to have had a very good career and let's hope it keeps going. I think he could manage until he's 101!"

Warnock returned to Boro's Rockcliffe training ground on Monday after recently testing positive for Covid-19 and Blackwell insists 'the gaffer' is fighting fit.

"He's very well. He's flying," Blackwell said. "Last week he wasn't brilliant at the beginning, but towards the end you could see the fire was coming back, it was re-lit and he's back at it again.

Warnock, front left, guided hometown club Sheffield United to the Premier League in 2006 (Nigel Roddis/PA)

"He certainly looks after himself fitness-wise and that's certainly helped him overcome Covid-19."

Warnock has won promotion with Scarborough, Notts County (twice), Huddersfield, Plymouth, Sheffield United, QPR and Cardiff.

His biggest attribute? "There's only one word needed – charisma," Blackwell said. "He has charisma and he's able to influence people and get them to believe in themselves more."

Warnock persuaded former goalkeeper Blackwell, who had made over 220 appearances for Boston, to sign for Scarborough in 1986.

Warnock's partnership with Blackwell, right, began in 1986 (Nick Potts/PA)

"He was able to sell the dream to me that he had no right to do and I think he can do that with most people," Blackwell said.

"People talk about Neil and Marmite and all the rest of it, but if you're playing for him, you're very happy.

"If you're playing against him, you hate him. That's the biggest accolade you can give him."

Blackwell vehemently disagrees with the widespread notion that Warnock would not be as effective managing top-end Premier League players.

"His biggest regret is getting to the Premier League and never being given serious funding," Blackwell added.

"Arsene Wenger used to say, 'If you want to know how good a manager you are, show me your players'.

"Successful managers must get the best out of people at all different levels and Neil has the skills and charisma in abundance.

"He's got to be up there with the best. He's the leading promotion-winner in football history and it's funny, when clubs are in trouble they soon come knocking."