He's very positive with his movement, darting across defenders into space and that is very difficult to defend against.
Rooney is the perfect foil for him because he drifts into the hole (shaded area in graphic, below) in front of the defence and picks Hernandez out with his passes. It also allows Rooney to arrive late from deep to cause trouble, as he did when scoring the goal at Stamford Bridge in the first leg.
Peas in a pod: Javier Hernandez (left) and Wayne Rooney have formed a superb partnership up front
That doesn't quite work as well when Rooney is partnered by Dimitar Berbatov because the Bulgarian likes to play in the hole and Rooney is left to make the runs in behind (graphic, below).
PREMIER LEAGUE THIS SEASON
Goals Goals/gameBerbatov.21 0.72Rooney.10 0.45Hernandez11 0.5
EUROPE THIS SEASON
Goals Goals/gameHernandez.3 0.5Rooney2 0.33Berbatov0 0
Antonio will always deliver
Any striker with movement as good as Hernandez is going to love playing with Antonio Valencia.
The Ecuador winger has only been back for six matches but the effect has been impressive. He consistently delivers excellent, teasing crosses and even looked solid filling in at right back in the first leg.
You can see the imapct he has had when you consider that in only 77 minutes on the pitch at Old Trafford against Fulham on Saturday, Valencia created more chances for his team-mates than any other player in the Premier League at the weekend.
The Valencia effect
Creative talent: Valencia is the king of crossing
Since moving to Old Trafford in the summer of 2009, United have been a stronger side with Valencia on the pitch.
With Valencia Without
Matches 39 31
Drawn 5 8
Win % 69 65
Points/game 2.21 2.19
He's only played five Premier League games this season since his return from a broken leg but has made an instant impact as United have neared a record 19th title.
Chances created . 15
Passes per match. 45
Pass completion %. 85
Tackles (win %).10 (80)
Shots to goals %. 50
Crosses per match 8
Dribbles per match 3.2
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Explore more:People: Wayne Rooney, Dimitar Berbatov, Antonio Valencia, Martin Keown Places: Ecuador