Sunderland and Millwall are back in Championship action on Saturday as they face each other at the Stadium of Light.

Both sides are returning from the World Cup break a week early for the clash on Wearside and they will be looking to carry on where they left off before Qatar.

Sunderland currently sit 15th in the table and they beat Birmingham City 2-1 at St Andrews' last time out, while Millwall, who are sixth, secured a 4-2 victory over Preston North End at Deepdale to move them into the play-off places.

Although they are inside the top six, it is only on goal difference and they are level on points with Queens Park Rangers, Swansea City and Preston, such is the tightness of the division this season.

The Black Cats are four points clear of the relegation zone, but are also only four points adrift of Millwall, so the game is a huge opportunity for Tony Mowbray's side to close the gap to the play-offs and put themselves back in promotion contention.

But what are some of the key battles that could dictate the result on Saturday?

Amad Diallo v Murray Wallace

It was a tough start to life at Sunderland for Manchester United loanee Diallo.

The 20-year-old, who scored three goals in 13 games on loan at Scottish Premiership side Rangers last season, initially found minutes hard to come by in the North East and faced competition for places from the likes of Patrick Roberts, Alex Pritchard and Jack Clarke.

However, he established himself in the side prior to the World Cup break and contributed with three goals and one assist in his last five games as he begins to show some of the potential which has made him such a highly-rated prospect at Old Trafford.

On his day, Diallo is a dynamic and exciting young player and if he is on form, he will give Lions left-back Murray Wallace a tough afternoon.

But Wallace has formed part of a back line which has only been breached 22 times this season, so it will be an intriguing battle between the pair.

Zian Flemming v Corry Evans

With both sides lining up in similar formations, it is likely that the midfield battle will play a part in determining the outcome.

There is no doubt who Millwall's key man is, with attacking midfielder Zian Flemming currently the Lions' top scorer with seven goals.

The 24-year-old, who signed from Dutch side Fortuna Sittard in the summer, notched a hat-trick in the 4-2 win over Preston and has made an outstanding start to life in the second tier.

Sunderland captain Corry Evans is likely to have a busy game, both in the physical battle with the likes of Billy Mitchell and George Saville, but in also providing defensive protection for his back four against Flemming.

With Andreas Voglsammer, George Honeyman and Tom Bradshaw also providing threats for Gary Rowett's side, it will be crucial to keep Flemming quiet.