Adrian Clarke looks at players who have been crucial to their team's tactical set-ups this season.
The South Korean energises Tottenham Hotspur in a way that no team-mate can.
Son's purposeful running and quality in front of goal are key features that Spurs miss when he is not in the side.
His versatility means that while he is at his best on the left wing, he is also effective on the right or as a striker.
In all competitions, the 27-year-old has netted five goals in five starts when played up front this term.
Son is the joint-quickest forward at Spurs, with his top speed this season of 35km/h matching that of Dele Alli.
But he is in a league of his own when it comes to making high-speed runs.
No player in the Spurs squad makes anywhere near as many sprints as he does.
This penetration helps him get into dangerous positions more frequently than any team-mate, touching the ball on average 6.69 times per 90 minutes in the opposition box.
|Top speed (km/h)||Sprints|
From a tactical point of view, Son also offers balance to Jose Mourinho's starting XI.
When Serge Aurier starts at right-back, the Portuguese head coach will often select a more defensive option on the left.
He does this safe in the knowledge that Son has the capability to cover that flank on his own.
His left-back can then drop off and make up a back three when required, making Spurs less vulnerable to counter-attacks.
Spurs' record with Son in the side is considerably better than when he is not.
They have scored more goals and won more matches with him playing.
|2019/20||Son starting||Son not starting|
|Av. goals scored||1.7||1.4|
|Av. points won||1.6||1.1|
Despite missing nearly a third of his side's matches this season, Son still tops a number of key categories for Spurs.
His 30 chances created, 51 shots and 29 shots on target are all more than any team-mate.
He also averages a goal every 193 minutes, second only to the 160 of Harry Kane, and is arguably the team's most competent finisher.
Comfortable shooting with either foot or attacking balls in the air, Son has scored a variety of goals across the campaign.
Son is perfectly suited to his dual role of being both a goalscorer and a creator.
Alongside his nine goals he has set up another seven, the joint-fourth most in the Premier League.
These qualities coupled with Mourinho's strategy have made Son an invaluable member of the Spurs side.