By the end of the campaign, Tottenham supporters might look back upon Monday’s late 2-1 victory at Watford as a crucial game. It felt like the moment Spurs became genuine title contenders this season, with Mauricio Pochettino almost sheepishly admitting “the numbers reflect that it is possible”.

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There are two entirely contrasting ways to view the win. The first is that it was a touch lucky: Son Heung-min's flicked winner came with just two minutes remaining, was struck from an offside position, after Watford had come within inches of scoring themselves, and came against a side who were reduced to 10 men for the final half hour.

For the first time at Spurs manager, Pochettino started with a three-man defence, dropping Dier back into his more natural position as a centre-back

The second way concerns the manner Spurs started the match. For the first time at Spurs manager, Pochettino started with a three-man defence, dropping Eric Dier back into his more natural position as a centre-back, and pushing his full-backs forward to become wing-backs. It was more 3-4-3, or 3-4-2-1, rather than the usual 4-2-3-1 – and Spurs dominated the first half.

Bielsa’s boy

Pochettino is famously a disciple of fellow Argentine coach Marcelo Bielsa, who he played under at international level, and one of the fundamental Bielsa principles is always ensuring your defence has a spare man at the back: two centre-backs against a lone striker, three centre-backs against a forward duo. And while Pochettino hasn't stuck to this principle previously, the fact that he was playing against the division's in-form strike partnership, Odion Ighalo and Troy Deeney, was surely the reason he opted to use an extra man at the back.

The key man, of course, was Dier. Having performed with incredible composure in his central midfield role, he nevertheless remains more comfortable at the back. Here, playing as a spare man either side of Toby Alderweireld and Jan Vertonghen, he generally took up covering positions as his central defensive colleagues stuck tight to the strikers, rarely having to make challenges on the ground but positioning himself well to make clearances.

Perhaps the most notable thing about Dier's use alongside Vertonghen and Alderweireld was the quality of the distribution from deep positions. The two Belgians are known for their quality on the ball, but Dier's experience higher up the pitch has made him better in possession too. He played some neat passes into the midfield zone, and also hit longer balls to the flanks in order to bypass Watford's midfield press.

Full-backs profit

The main beneficiaries of Dier's deeper positioning, though, were Danny Rose and Kieran Trippier. Both naturally energetic, attack-minded full-backs, they both pushed higher up the pitch, stretching the play and allowing Spurs' regular wingers inside into more narrow positions – from where Erik Lamela opened the scoring.

The advanced positioning of the wing-backs was notable throughout, particularly from the number of crosses they played into the box. Rose needs to improve on this area of his game significantly, but Trippier impressed with some tremendous whipped balls into the penalty box – and his final ball of the day was converted by Son for Spurs' late winner.

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By this stage Dier was spending plenty of time in midfield, as Spurs were playing against 10 men and pushing forward for the winner. His versatility could be absolutely crucial for Pochettino over the next five months, giving him the option to switch between a three-man defence and a back four without having to change his personnel.

It might also be useful for Roy Hodgson, too. With Jack Wilshere's latest injury setback meaning England are struggling badly in the deep midfield position ahead of Euro 2012, Dier could be selected in the knowledge he can cover two positions, meaning Hodgson can take an extra attacking player. Continued assured performances for Spurs, in either position, and Dier might even force himself into England's first XI.

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