Swansea City's match with Manchester United this weekend is likely to be decided by how the visitors defend.
Swansea travel to Old Trafford as the underdogs, but they will feel that they have a chance of taking some points back to Wales if they can build a solid platform.
United have lost just once in their last 19 games, but their performances have often looked short of the quality required to claim a top-four place and they still do not appear to be in full flow under Louis van Gaal's stewardship.
Swansea will know that if they can put in a display which shows the quality that they have in their ranks they will have a chance of success.
The Welsh outfit have had an impressive season so far, but without Wilfried Bony they look much less of a threat in attacking situations and it means that the structure of their team will become much more important.
Swansea do not have the firepower to outscore teams regularly and they will now be relying on their defenders to step up to the plate and help keep more clean sheets.
Crucial to this will be the form of Ashley Williams. The centre-back has become a key member of Swansea's squad over the years and he looks like the most classy operator of all the defenders in their ranks.
Williams boasts some impressive statistics this season, with the 30-year-old having high figures in a range of areas.
|Headers won per game||Interceptions per game||Defensive duels won per game||Tackles per game||Appearances||Mins Played|
He is a combative defender and his ability to win so many headers, interceptions and tackles every match is pivotal to Swansea's success.
His job this weekend looks a tough one though. United's strikers may not have hit their top form, but they are still amongst the most dangerous in world football on their day and Williams will need to put in a display of the highest quality to keep them quiet.
Williams's biggest task is likely to be stopping Wayne Rooney. The England international could well be restored to the striking positions after having to play much of the campaign in central midfield and he will be determined to impress.
With Radamel Falcao and Robin van Persie both struggling for goals, Rooney is expected to lead the line on Saturday, and defending against a player of his quality is always a tough task.
Although the England international's tally of eight goals and four assists for the season is not his best, he has still put in some good performances and his displays have always been of a high class.
|Goals||Chances created per game||Dribbles per game||Passes per game||Passing Accuracy||Assists||Headers won per game||Defensive duels won per game||Appearances||Mins Played|
Rooney distributes the ball well and he is a constant threat in attacking situations, with his creative ability shown in the fact that he forges a good opportunity for his teammate more than once a game.
If Williams can keep Rooney at arm's length, Swansea will feel confident of success, but if their captain struggles to keep him on a leash then United could coast to victory.