Paul Merson has backed Jose Mourinho to turn Tottenham into winners - but only if they embrace his playing style.
Mourinho has faced criticism over Tottenham's poor performances ahead of the north London derby, live on Sky Sports on Sunday, with Thursday's goalless draw against Bournemouth another blow to their hopes of European qualification.
Spurs have only won two of their last eight Premier League games either side of football's suspension and Mourinho's methods are under scrutiny after they failed to register a single shot on target at the Vitality Stadium.
But Merson, whose recent comments on Harry Kane prompted Mourinho to defend his record with strikers, believes the 57-year-old's defence-first approach will eventually pay off for a club who have not won silverware in over a decade.
"I think they're slowly changing the way they play," Merson said on Soccer Saturday.
"When (Mauricio) Pochettino was there it was different. Mourinho's come in and he plays a different way. But if he'd have won that game [against Bournemouth] 1-0, he would have been happy as Larry. He doesn't want to be involved in 5-2s and 6-3s.
"He talks exactly the same as (Mikel) Arteta. If you're good defensively, you've got much more chance of winning football matches.
"I think he's just starting to put his footprint on this team and I think they are going to be very hard to beat. They're not going to be the entertaining team, but that's the way it is.
"Mourinho has won everything in the game. You don't go into Tottenham and change your way of playing for players who have never won anything. You make sure that they play your way and you win them trophies.
"People go, 'you can't win like that anymore, winning 1-0 and 2-0'. You can, believe me. No one ever wins anything with a bad defence."
Spurs sit ninth in the Premier League table ahead of Sunday's derby.
Merson admits Mourinho has not yet reversed the decline that set in at the end of Pochettino's reign, but the former Arsenal midfielder believes the club's supporters need to trust him.
"They were going for Premier League titles and Champions Leagues for the last two or three years, so of course they are still in decline at the moment," he said.
"But with Mourinho there, he will turn it around. He will, but they have to play his way.
"Totenham aren't going to be a free-flowing side. But they've got to trust Mourinho and have faith, because this man has won everything and they've won nothing."
Watch Tottenham vs Arsenal live on Sky Sports Premier League and Sky Sports Main Event from 4.15pm on Sunday; Kick-off 4.30pm