Chris Dagnall fired Leyton Orient back to the top of League One with two goals on his debut to the delight of manager Russell Slade.
The former Barnsley striker netted twice inside seven second-half minutes to cancel out Byron Moore's opener and sink Crewe 2-1.
"That is what Chris is all about. He gets behind defenders and is very lively. He is going to be a great acquisition for the club," said Slade.
"It's great to go back on top and it was a really hard-earned result as Crewe were excellent. They put us under a lot of pressure, particularly late on in the game and we had to come from behind yet again.
"Our fans were fantastic all afternoon and in the last five minutes they counted massively for us as Crewe sent on a lot of big players and we had to pick them up on free-kicks and corners. We had to hang on."