The England striker pounced in the 73rd minute after being set up by Cristiano Ronaldo, with United rallying to victory after Nemanja Vidic was needlessly sent off for a deliberate elbow early in the 2nd half. Rooney's goal gave them an unprecedented treble this year, with the English Premier Leaue and European champions now able to call themselves world champions, helping silence those who have criticised the long trip here.
Sir Alex Ferguson's men also became the first British team to win the tournament, putting them alongside Italy's AC Milan and Brazil's Internacional and Sao Paulo. "The collective spirit of the team won the day," said Ferguson. "With 10 men we played with great expression and tried to win the match, which is a measure of the ambition of the players we have. After Vidic was sent off it was important that we didn't lose the ball. It was important to keep passing and hope Ronaldo or Rooney did something special."
Wayne Rooney was overjoyed at scoring the winner. "To be crowned the best in the world is a great achievement," he said. "To score the winning goal in a match like this is a great feeling for me personally."
Conscious that he needs fresh legs for Stoke City on Friday, Ferguson made a number of changes to the side that beat Gamba Osaka on Thursday, with Gary Neville, Ryan Giggs, Paul Scholes and Nani relegated to the bench. On a windy night, Ronaldo was clearly a marked man and was heavily tackled twice in the opening minutes as the Ecuadorians made their intentions clear. It was Liga de Quito who created the first chance on four minutes when Jairo Campos beat the offside trap from a freekick but fluffed his shot.
United though soon found their feet and Rooney chested down a through ball from Vidic just inside the box on 10 minutes and unleashed a fierce shot that goalkeeper Jose Cevallos did well to punch away. He tested Cevallos again minutes later when he sent another powerful drive towards goal which the keeper deflected for a corner. Ronaldo was putting on a show for the 68,000 fans, employing his full bag of tricks, and it was the Portuguese winger who whipped in a cross to Carlos Tevez on 19 minutes, with his shot forcing a spectacular save.
Soon after, Rooney tried a cheeky lob as Cevallos rushed out, only to see the ball hit the top of the net. Park Ji-Sung should have put United one up but volleyed over from six yards and the two sides went to the break all square. United got off to the worst possible start in the second half when Vidic was given a straight red card on 49 minutes for elbowing Claudio Bieler.
The Serb gets an automatic one-match UEFA ban which means he will miss United's Champions League first leg tie against Inter Milan in February. Despite being down to 10 men United knuckled down, with Ronaldo troubling Cevallos with a long range strike and Rooney getting a header on target. With the game looking like it could go to extra time, Michael Carrick slipped the ball to Ronaldo who deftly laid it off to Rooney who made no mistake, side-footing into the right hand corner.
Liga coach Edgardo Bauza admitted United deserved to win but praised his team. "Manchester United is a fantastic team. We had a very good second half, we gave everything and we are very satisfied," he said. The win earned United five million dollars, with Liga taking home four million.