The Argentinean full-back was shown a straight red after bringing down Paul Scholes as he attempted to latch onto Ruud van Nistelrooy's pass in our 4-0 defeat.
The striker, on the bench last night, explained: "I was warming up at the time and it was a yard and a half outside the box.
"When I saw the referee blow I knew it was going to be a free-kick but I never thought he would give a penalty. It was an outrageous decision."
Les came on for Sergei Rebrov at half-time and had a chance within a minute of the re-start but, as he admitted, it was an uphill struggle for our ten men to contain a rampant United.
He added: "In the first 15-20 minutes we looked like upsetting something, we passed the ball around well, they didn't really threaten and we looked quite comfortable.
"But to go a goal down, then down to ten men, then a penalty to make it 2-0 makes it tough. It's difficult at Manchester United at the best of times but after that it was always an uphill battle."
Les Ferdinand had a better view than most of Mauricio Taricco's controversial red card incident at Old Trafford.