Dwindling Mata supply lines to blame for Rooney drought
After 18 months playing together at United, that goal remains the only one that Mata has created for Rooney in the Premier League.
Rooney's current goal drought now stands at 858 minutes, stretching back to his strike against Aston Villa at Old Trafford on April 4, and the 29-year-old's contribution so far this season has amplified calls from United supporters for Van Gaal to recruit a proven goalscorer during the final week of the transfer window.
The Dutchman insists he retains faith in Rooney to score at least 20 goals this season and that his team's dominance of opponents will soon be rewarded with the goals.
Van Gaal believes that the goalscoring problem can be resolved with current personnel, but Mata's role is likely to come under growing scrutiny due to his inability to play the provider for Rooney.
Since arriving in the Premier League at Chelsea from Valencia in the summer of 2011, Mata has created 36 league goals.
At Stamford Bridge, the Spaniard's contribution saw him become the team's creative force, with 27 Premier League assists in two-and-a-half seasons.
Largely deployed in a central role behind the centre-forward, Mata was able to pick holes in opponents' defences for team-mates to exploit.
At United, Mata has largely been denied that 'No 10' position by Van Gaal and, previously, David Moyes; his assists have dropped to just nine in 18 months.
While the 27-year-old has maintained his threat as a goalscorer, netting 15 league goals for United compared to 18 for Chelsea, his impact as a creator has diminished.
Rooney, it would now appear, has become a victim of Mata's reduced output.
The pair also suffer from a shared desire to drift towards the 'No 10' position that neither is being asked to play by Van Gaal.
The United manager wants Rooney to play as his team's focal point, with Mata positioned on the right flank, but the formula is struggling to work.
What is clear is that Rooney requires better service - he needs Memphis Depay to find an earlier pass, as well as Mata - but the England captain must also be disciplined enough to avoid dropping deep in search of the ball.
However, if Van Gaal can find a way to move Mata inside, it could end Rooney's slump. (© Daily Telegraph, London)