Alexi Lalas Basks In Wayne Rooney Trash Talk, I Made Him Better!

Remember when Alexi Lalas said Wayne Rooney was washed up -- and explained why it would be a mistake for D.C. United to sign him???

Yeah, so do we ... that was in May before Rooney joined the MLS and SET THE LEAGUE ON FIRE!! Since then, Rooney's been a beast on the pitch -- so we went to Lalas to see how he felt about being so wrong.

His response was amazing.

"This would not be the first team that should be paying me in order to be motivating their players," Lalas joked ... "So I say, 'You're welcome D.C. It's my gift to you, it's my gift to you, Wayne, and my gift to soccer.'"

The 32-year-old has already racked up 3 goals and 3 assists in the 8 games he's played with D.C. United -- and the team is 5-2-1 in games Rooney has played in.

Plus, the INSANE play Rooney made during the August 12 game against Orlando City S.C. went crazy viral and some are hailing it as one of the greatest plays in MLS history.

It all went down during stoppage time of a 2-2 tie ... when Rooney chased down an opposing player around midfield, stole the ball with a slide tackle and fired up a 50-ish-yard cross to a teammate who headed the ball for the game-winning goal.

Ya gotta watch ... it's nothing short of spectacular.

On a serious note, Lalas says Rooney's presence is making his teammates better -- and the sky is the limit for D.C. United.