The decision not to award a penalty for Alex Oxlade-Chamberlain's foul on Luis Suarez in the penalty area has caused controversy. So too did the subsequent decision not to send Steven Gerrard off late in the game.
Maybe he was thrown off by Raheem Sterling's Jedi mind trick here at the end of the first half.
Sterling briefly puts his hand on Webb's chest. Webb lifts it away, confused.
And then things went horribly wrong.
Hat-tip to 101 Great Goals for the gif.