Aston Villa have been the Premier League's surprise package so far this season.

Unai Emery's outfit moved up to fourth with their 2-1 win at Tottenham last Sunday and are the joint second-top scorers in the division with 31 goals.

Ahead of their meeting with Legia Warszawa in the Europa Conference League this evening, we take a closer look at how the Villa boss has masterminded the club's transformation.

High line

Villa's well-executed high line since Emery took charge has proven to be a nightmare for opposing teams.

As well as helping the team spring forward with the ball even quicker, the risky tactic has been hugely beneficial from a defensive standpoint.

Villa have caught opposition players offside on 165 occasions in the Premier League during Emery's reign, 72 more times than any other side.

Last weekend, the high line saw Spurs captain Heung-Min Son have three goals disallowed for offside.

However, the Villa boss will be aware his side are still a work in progress defensively, as they have shipped 18 goals in 13 league matches and kept only two clean sheets.

Terrific Torres

While he has not helped the team keep more clean sheets, centre-back Pau Torres has been key to Emery's men reaching new heights.

Signed from Villarreal in July, his ability on the ball has seen Villa evolve into a different beast in possession, while his defensive class has softened the blow of Tyrone Mings' serious knee injury.

Whether lining up in Emery's favoured back four or in a back three — like he did against Spurs — Torres' calm nature brings out the best in those around him, most notably Ezri Konsa.

The Spaniard ranks ninth in the Premier League for passes completed, while also sitting sixth among centre-backs in the division for final-third passes executed.

Emery said in September: "We needed from him [Torres] the skill to build up with the goalkeeper and combine with the midfielders."

Midfield maestros

Further forward, Emery's implementation of a narrow four-man midfield has really paid dividends.

The quartet of Boubacar Kamara, Douglas Luiz, captain John McGinn and — more recently — summer signing Youri Tielemans allows Villa to dominate the middle of the park, while also affording full-backs Matty Cash and Lucas Digne space to bomb forward.

Moussa Diaby is often the forward tasked with dropping a bit deeper to support the midfield in a No10 role, with his three league goals and three assists evidence of his quick adjustment to the manager's specific demands.

McGinn and Luiz have also contributed heavily in the final third, the former with five Premier League goal contributions this term and the latter a hugely impressive seven.

Focal point

Star striker Ollie Watkins is also thriving in Emery's system.

The England international's ability to link play when dropping deep and willingness to run the channels are tailor-made for his manager, who he admits has taken his game to another level.

Watkins recently said: "He [Emery] tells you how to play, where to stand and how to get the best out of your game."

The ex-Brentford marksman's 13 Premier League appearances this term have yielded seven goals and five assists — and with him as the focal point of Emery's blueprint, the Champions League dream could become reality.