#4 Romelu Lukaku
Well, the question 'where is the young player who scored a hat-trick as a substitute against Manchester United?' becomes redundant in this case. Because it is known to all that Romelu Lukaku is now an Old Trafford fan favourite.
The big Belgian scored a hat-trick against the Red Devils as a 20-year-old in a 10-goal-thriller that ended as a 5-5 draw at the Hawthorns on 19 May 2013.
Old Trafford faithful will remember this match for years to come, because it was the final and 1,500th game in charge of Sir Alex Ferguson, in which the then Chelsea loanee denied the Scot a winning end to his splendid career.
But for Chelsea, the three goals scored by Lukaku, that too as a substitute against Manchester United wasn't enough and he was loaned out to Everton in 2013-14, where he was signed permanently in the next season.
After spending three seasons at the Goodison Park, he established himself as one of the best strikers of the league and was signed by his former coach Jose Mourinho.
Since his hat-trick, he has become the top-scorer for the Belgium National team and helped them secure a third-place finish at the recent World Cup.