Both Manchester City and Southampton can be relatively happy with their seasons, on the whole, so far with the fortunes having been favourable.

Recently the runs of both teams have taken a rather unexpected turn. City have now failed to win in four games heading into the match game with the Saints with the most recent defeat being a drubbing by Barcelona at the Nou Camp on Wednesday evening.

Claude Puel on the other hand has finally found his feet at St. Mary's Stadium having taken over the reigns from Ronald Koeman, who departed for Everton. The team has been rebuilt under the Frenchman and with a new identity, they have once again managed to maintain solidity on the south coast.

Although both teams are in the top half of the table their aspirations are very different, but it certainly looks set to be a closely contested battle between the pair. Here are some key battles ahead of this clash at the Etihad Stadium...

Sergio Aguero vs. Virgil Van Dijk

Sergio Aguero misses penalty v Everton

These two could fit into any side in the league. Sergio Aguero has struggled in recent weeks and rumours are circulating the Argentine international is not getting along with manager Pep Guardiola. Despite netting 11 goals in nine games, Aguero's confidence has looked shattered of late after a number of penalty misses for both club and country.

Van Dijk is one of the league's best defenders and the battle between the two will be an interesting one to witness. The winner of this duel may well determine the winner of the entire contest.

Pep Guardiola vs. Claude Puel

Pep Guardiola and Sergio Aguero

The big question this week will be whether Guardiola reverts to his typical 4-3-3 formation after being completely undone by Barcelona in midweek. City may have lost 4-0 but credit to them as they didn't deserve the humiliation the scoreline brought.

The fact remains Guardiola's tactical knowledge knows no bounds and his French counterpart is well renowned for his clever systems. Puel's tactics have enabled Southampton to develop once again and his ability to ensure solidity may see a re-run of last weekend's 1-1 game at the Etihad Stadium between the Citizens and Everton.

Whoever boss ensures their side is set-up set up correctly will likely walk away with three points.

Claudio Bravo v Fraser Forster

Claudio Bravo

Both goalkeepers come into this in different runs of form. Bravo's move to Manchester City is yet to fully get going as the Chile international is struggling to recapture the form he showed at Barcelona so regularly.

Major errors have led to goals in recent weeks, most notably in the Manchester Derby. A red card in midweek contributed to City's downfall at the Nou Camp, too, and ended their chances of securing a result in Spain.

Forster, on the contrary, has conceded just one goal in 700 minutes of Premier League football after Burnley scored a consolation last Sunday. Forster's form has seen a number of people call for the Southampton stopper to become the country's No.1.

Full-backs v Full-backs

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Manchester City's Aleksandar Kolarov in action with Manchester United's Henrikh Mkhitaryan 
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Pep Guardiola's biggest weakness in his City squad remains his full-backs. The ageing defenders have constantly been an element of weakness despite the fantastic form of their centre-back pairing.

Southampton's left and right-back positions have been a sturdy part of their squad since their return to the Premier League. Ryan Bertrand and Cuco Martina have become linchpins in their success in recent months and both players add another attacking dimension to the side, whilst offering security in wide positions.

City can only dream of full-backs like Southampton's and the winners of this contest could have a big impact on the entire game.

Fernandinho v Steven Davis

Fernandinho Guardiola Instructions

If you're looking for two of the most consistent performers in the Premier League, then look no further than this midfield duo. The duel between these two will make interesting viewing as their work-rate and stamina have catapulted their respective teams up the Premier League table.

Fernandinho is the only player to play every league minute under Guardiola and symbolises the Spaniard's philosophy of dedication, passing and versatility.

On the other hand, Davis has become a strong performer for Southampton in recent months and without his expertise, the Saints may not have been able to pick up as many points as they have. This is certainly one battle to keep a close eye on.