Manchester United boss Louis van Gaal says he replaced Memphis Depay at half time because he wanted more efficiency in the final third.
The Red Devils moved up to second in the table after a convincing 3-1 win at home against Liverpool.
And Anthony Martial was the hero for United as he marked his debut with a brilliant goal.
"We played better in the first half," van Gaal said after the game.
"We had far more control, but we didn't create much, that is why I changed Memphis - to improve that last pass.
"When you make a goal like Anthony you cannot wish for more, I think. A lot of players have made a debut and scored with me so it's a good signal."