Jermaine Jenas: Tactical genius Pochettino is a game changer for Tottenham

There was a clear sense of unease among many Tottenham fans going into the weekend north London derby. Arsenal were in top form, while Mauricio Pochettino's side looked a shadow of last season's effervescent team, their Champions League display against Bayer Leverkusen being one of their worst since the Argentine manager arrived at White Hart Lane.

Something drastic was needed to tilt the balance in Spurs' favour at the Emirates, and Pochettino delivered it. His tactical move to play three at the back turned out to be a masterstroke that underlined their credentials as title contenders.

In terms of the derby, Spurs were almost lucky that defeat to Leverkusen came when it did. It was the slap in the face their players needed.

It's possible that after beating Manchester City a month ago, Spurs got a bit carried away. They still haven't won a match since then, but they came out at the Emirates looking like a completely different beast to the one that went down with a whimper at Wembley four days earlier.

Formation change rejuvenates Tottenham

The credit for this must go to Pochettino. He showed he has the ability as a manager - and that his players have the ability - to be adaptable. And not just in any game but in the biggest one of all - against Arsenal at the Emirates.

This new formation can be a game changer for Tottenham. Other sides have got to know how they play - even if they can't always stop them - but they have pulled another weapon out of their armoury, almost from nowhere. This is now a formation they can go to at any time, whether during a game or at the start.

As a player, suddenly being asked to play in a different formation isn't easy. Everton tried moving to a three-at-the-back system against Chelsea on Saturday and they looked like they didn't have a clue how to do it, losing the match 5-0.

It also happened to me when I moved to Spurs from Newcastle, where they always played 4-4-2. At White Hart Lane, I was employed in more of a 4-3-3, alongside Michael Carrick and Edgar Davids in midfield, with me on the right side of it.

I was used to dropping back to pick up the ball from the back four, but Carrick was doing that job. So positionally, I was finding myself in situations that felt quite foreign. I had to half tuck in and half go out wide, and I didn't know who to mark.

So it can be hard to adapt, but what helped Spurs at the Emirates was that their formation was not so wildly different to their normal system.

Midfielder Eric Dier would often drop deep in their regular formation, allowing the full-backs Kyle Walker and Danny Rose to push on. That's essentially three at the back already.

Rose and Walker are great at going forward as well as defending, so the wing-back role suits them. This meant that against Arsenal, as well as being more solid defensively, Spurs also looked better going forward than they have in recent weeks.

Not that I see them sticking with this formation long-term. Pochettino has been very successful with the 4-2-3-1 system at Spurs and I expect to see it return. But in many ways playing three at the back suits the players they have, and against the Gunners it worked perfectly.

Influential Wanyama wins midfield battle

Arsenal may have been in better form of late, but we learned on Sunday that their central midfield is nowhere near as good as Tottenham's. Francis Coquelin had a decent game, but Victor Wanyama, Mousa Dembele and Christian Eriksen, playing in a slightly deeper role, were dominant.

When you look at the two major midfield signings the sides made in the summer, Wanyama looks a far better purchase than Granit Xhaka.

The Kenyan was brilliant at the Emirates. He seems to have added a calmness and maturity to his game that was sometimes lacking at Southampton. He's less crazy and far more assured, to the degree that he already looks like the main man in that midfield, alongside Dembele. He has managed to dislodge Dier, which is no mean feat after the season he had last year.

But it all balances out, because Alexis Sanchez was outstanding and right now the Gunners look better in attack. Harry Kane's return will boost Tottenham on that front. It was a promising comeback display from the centre-forward, and he gave Spurs a physical presence that allows them to be more flexible and play more direct when necessary.

I spoke to Pochettino recently and he is a man who prides himself on the mentality of his team. He can accept losing, but he can't accept poor professionalism, and I think that's what upset him about the Leverkusen game.

He will be massively proud of his team for the way they have responded, and it will also give him a good indicator of where they are heading. This was the performance that proved to me that Spurs will be challenging for the title. Arsenal will be too.

These great rivals look very evenly matched at the minute. They could both win the league, but the positive thing for Spurs is that they have had their blip - and they seem to have come back from it strongly.