#2 Anthony Martial (Forward)
Anthony Martial signed for Manchester United for the sum of £57.6 million in 2015 which made him the most expensive teenager in history at that point.
He had earlier shown a lot of promise with Monaco which led to him being named the Golden Boy in 2015 and he continued his bright start at Manchester United, scoring a brilliant goal against Liverpool on his debut and ending his first season at Old Trafford with 17 goals from 49 appearances in all competitions.
The arrival of Jose Mourinho at Manchester United affected a lot of players' growth and Anthony Martial was arguably the worst it. He struggled for form, with his dire situation at United costing him a spot in France's Word Cup winning squad.
This season continued in pretty much the same manner, but despite his differences with Mourinho, the French international continued to star on the pitch and was the club's leading goalscorer in the league prior to Mou's departure with seven goals.
Even though injuries have been unkind to him in recent weeks, Martial still possesses enough quality to harm Barcelona and would be buoyed by his recent five-year contract extension and the Blaugrana defence must do their best to keep him in check.