He wasn’t quite kryptonite to Guardiola’s Superman but it’s certainly true that Pochettino was the first coach to really get the measure of Pep in Spain, and he did it despite having significantly poorer resources and when it was least expected.

Back in 2009 Barcelona were on course to win the treble and had gone six months unbeaten. Espanyol turned up at the Nou Camp in February not having won there in 27 years.

Pochettino had only taken over the previous month with Espanyol at the foot of the table – he knew the bottom club had never beaten the leaders in La Liga history and his team were not given a chance.

Mauricio Pochettino and Pep Guardiola in a clash between Barcelona and Espanyol in 2009

Ivan De La Pena celebrates scoring in Espanyol's shock 2-1 win over Barcelona that night

But against all the odds Espanyol ran out 2-1 winners and showed La Liga there was a way to stop the Guardiola juggernaut.

Up to that point teams had attempted to defend as deep as possible against them camping two banks of four on the edge of their own penalty area hoping to squeeze the space between the lines where Lionel Messi was so effective, and closing all possible corridors of opportunity for a Xavi pass or an Iniesta through-ball.

But Pochettino tore up that blueprint. Instead he sent his team out to press high not giving Rafa Marquez, Gerard Pique or holding midfielder that night Yaya Toure time on the ball to bring it out with composure.

The plan was helped by by Barcelona being reduced to 10 men when Seydou Keita was sent off after 38 minutes but the achievement was still huge.

Barca midfielder Xavi trudges off the field as Espanyol celebrate their shock triumph

Lionel Messi shows his frustrations during Barcelona's derby defeat in February 2009

MATCH FACTS Barcelona: Valdes, Abidal (Puyol 24), Dani Alves, Pique, Marquez, Xavi, Messi, Keita, Yaya Toure, Henry (Busquets 46), Eto'o (Gudjohnsen 65) Goals: Yaya Toure 62 Sent off: Keita 38 Espanyol: Kameni, Jarque, Nicolas Pareja, David Garcia, Sanchez, De La Pena (Coro 72), Angel (Martinez 36), Nene (Raul Tamudo 88), Moises Hurtado, Alonso. Luis Garcia Goals: De La Pena 50, 55 Advertisement

The plan had also been to leave two or sometimes three players high up the pitch even when Barcelona were attacking.

It was risky but it helped Espanyol launch quick counter attacks when ever they managed to win the ball.

'It was a very demanding game. Now we have to pick ourselves up as best we can,’ said Guardiola after the match.

‘Espanyol showed the world how to beat Barca,’ read the match report in El Periodico, although it wasn’t all praise for Pochettino’s tactics with complaints from the Barca-supporting press that Espanyol had been more interested in wasting time and breaking the play up, than playing football themselves.

Messi and team-mates Eidur Gudjohnsen and Gerard Pique look dejected at full-time

Seydou Keita is shown a first-half red card much to Barcelona's displeasure

The Tottenham boss was the first to get the measure of Guardiola in La Liga

The pair embrace ahead of one of their many clashes during their time together in Spain

The overall balance of results tended to go in Guardiola’s favour from that day on. Against Pochettino’s side he picked up five wins, three draws and just that one defeat in nine games.

PEP V POCH Played: 9 Pep wins: 5 Draws: 3 Poch wins: 1 Advertisement

But the Argentine coach’s teams always made it difficult. Right up until January 2012 when his side played out a 1-1 draw at home against Barca team that had by then won the European Cup twice in three years.

Again the emphasis had been on pressing high with pace and this time putting pressure on Sergio Busquets, who had replaced Toure in the team. Courage and supreme fitness were required to make the plan work but Pochettino and his players had both qualities.

Teams still use the tactic against Barcelona – gone are the days when side retreat as far as possible against them.

The pair shake hands on the pitch ahead of the derby between Espanyol and Barca

Busquets in particular is now hassled in possession and in midweek he was robbed midway inside his own half and Borrusia Monchengladbach scored from the subsequent breakaway.

And Pochettino is still preaching his gospel of high-energy hunting down of both the ball and the opposition.