Yes, he was partly to blame because he was slightly out of position having moved too far right and therefore far away from central defensive partner John Terry.
Gone in 36 seconds: Hernandez stuns Chelsea with early strike
But Terry should have addressed this in one of two ways. If he felt Luiz was out of position, he should have shouted at him to move out and get in line to play the offside trap. Or he should have got in line with Luiz so he could have helped him out. You are supposed to line up with the man who is marking the striker and that was the Brazilian.
So both were at fault, even though it was Luiz who paid the price, being removed at half-time. That was a harsh move from Ancelotti and left him with few options late in the game when it came to substitutions.
Meet the Incredible Tackling Man
Pick pocket: United's Ji-Sung Park (Lleft) challenges Frank Lampard
Park Ji-sung is the Incredible Tackling Man. He broke up the play brilliantly again yesterday and his intensity and energy is the same in the first minute as the 90th. The Korean plays in all United's big games and tucks in off the flank almost unnoticed to pick people's pockets.
Sir Alex Ferguson and Ryan Giggs deserve the credit for how the Welshman has been reinvented as a central midfielder.
Everything goes through him, he was superb yesterday and his passes are so clever.
They missed him against Arsenal and he's now in a race with Ferguson to see who can last longer at the club. United need them both for as long as possible.
No, Chelsea have not won anything this season but they have not been far off. It would be wrong for Carlo Ancelotti to lose his job now.
Few players will give Ashley Cole as tough a time as Antonio Valencia did. If he had not been injured, United would have won the title weeks ago.
Manchester United 2 Chelsea 1: Title all but decided as Blues limp out of race with a whimperMartin Samuel: Fergie hasn't just knocked Liverpool off their perch, he's let a cat in the cageJust champion! The title is ours - we won't slip up, roars FergieFive key moments that propelled United to Premier League glory
Explore more:People: Alex Ferguson, Park Ji-sung, John Terry, Ryan Giggs, Antonio Valencia, Ashley Cole, Carlo Ancelotti