Paul McGrath: Matt Doherty’s biggest challenge after his move to Spain

But there is one ‘but’ – Matt has got to play in Spain.

He’s now at one of Europe’s great clubs, but he has to be playing, not sitting watching his team in action on the bench.

This afternoon his old team-mates have to win this great contest that will have a huge bearing on the rest of the season for both sides.

Spurs are slipping behind Manchester United in the race for that vital fourth place in the Premier League that brings with it Champons League football next season.

Without the Champions League next season, does Conte walk away, does Harry Kane look for a transfer, does Hugo Lloris leave?

Just as the London club needs to win, so we wait for the start of Manchester City’s big run to the title.

And we wait, and wait, and here’s another match where the Sky Blues could lose ground on Arsenal – not gain it.

You may blame the winter World Cup for ‘City’s troubles.

Neither they nor Liverpool have been at anything like their strength of the last few seasons this term.

Yet Manchester City’s best player, Erling Haaland, didn’t go to the World Cup.

Nor did Liverpool’s in Mo Salah.

And the World Cup cost Arsenal the services of their injured striker Gabriel Jesus for a couple of months.

But it is the Gunners who still lead the table.

After Arsenal’s defeat at Everton on Saturday, City now have a chance to close the gap at the top.

They do still have to play Arsenal twice, but things are getting touchy at the Etihad.

We know that because of Joao Cancelo’s shock loan move to Bayern Munich last Tuesday.

Ten days ago, there were no backroom soundings at all that the Portuguese full-back and wing-back would leave.

There was clearly a bust-up with the manager, there can be no other explanation for it.

The last time I can remember a player leaving in his prime, on such short notice, was when Alex Ferguson got rid of his Dutch centre-half Jaap Stam during pre-season.

That was because of stuff Stam wrote in an autobiography.

This time it was clearly just words said between player and manager.

But shipping out a player at short notice doesn’t sit well in a professional football dressing-room.

What players usually think in that case is ‘will he come for me next?’

When it happens, players then aren’t focused on their main task – to win matches.

Pep Guardiola has been a brilliant manager, with Barcelona, Bayern Munich and Manchester City.

And part of his genius with all three clubs was to keep a squad laden with superstars focused on only one thing – winning trophies.

Clearly Cancelo’s departure is the first hole in the dyke at City.

You have to wonder if it will be costly in the end, as City chase the Premier League, the Champions League and the FA Cup.

We’ll get a clue today. If Spurs win, a fifth title in six seasons may be beyond Man City.

They would have just too much ground to make up on Arsenal - and too few games in which to do it.