The Premier League is back.

After what feels like an endless summer of transfer madness, the window is shut and the focus can finally return to football for at least a couple of months.

Chelsea kick off their campaign with a tricky test against Manchester United at Old Trafford, looking for the perfect start under Frank Lampard.

Pre-season has been a mixed bag for the Blues, with two contrasting stories at either end of the pitch.

Going forwards, Lampard has had his side playing fast, attacking football and that approach resulted in Chelsea finding the back of the net 18 times in six games, with Ross Barkley top scoring with four.

Defensively however, the Blues have looked vulnerable at times and set pieces have been a major cause for concern.

Pre-season is rarely an indication of how the competitive campaign will play out, though, and Lampard will be hoping his side have put any defensive woes behind them.

Ahead of this weekend’s clash at Old Trafford, we’ve taken a look at a number of key battles to look out for.