Sam Allardyce feels 10-man West Ham's 2-1 win over derby rivals Millwall could prove a "defining moment" in their Championship promotion bid.

The Hammers were forced to play for almost the entire match a man down after skipper Kevin Nolan was sent off for a two-footed lunge.

Millwall looked to have pinched a point when Liam Trotter cancelled out Carlton Cole's first-half header. But centre-half Winston Reid crashed in a superb winner in the 69th minute as the West Ham consolidated their place at the top of the league.

"It was a result we deserved," said Hammers boss Allardyce.

"We managed the disappointment of Kevin going off, we didn't sit back and we got our reward.

"It could be a defining moment. There's a pressure in this fixture and you have to handle that."

Happily there was no repeat of the crowd trouble which marred the last meeting between these old foes at Upton Park, in the Carling Cup in August 2009.

Nevertheless, the derby-day atmosphere clearly got to Nolan as his rush of blood left his team-mates to play more than 80 minutes a man down.

The Hammers shipped five goals in a shock defeat at Ipswich on Tuesday night and were desperate to get back to winning ways to cement their place at the top.

So the last thing they needed was to see their captain and most experienced player given his marching orders after just nine minutes.

Nolan may have got some of the ball, but he also got a lot of Millwall defender Jack Smith and both his feet were off the ground as he slid in, giving referee Mick Jones no choice but to brandish the red card.

Yet Allardyce insisted the former Newcastle midfielder should not have been sent off.

"He was in control, it wasn't over-vigorous," he added.

"But it looks like the refs are told to red card that now. It's going to spoil the game."

Following a shaky start, the Hammers actually improved after Nolan had trudged off and took the lead in first-half stoppage time when Millwall failed to deal with Mark Noble's free-kick and Cole pounced with a header.

Julien Faubert then hit the crossbar for the hosts but they were pegged back in the 66th minute through Liam Trotter's volley.

However, three minutes later, keeper David Forde was clattered by Faubert as he punched the ball, which landed at the feet of Reid who lashed it home first time for the winner.

"It was definitely a foul on the goalkeeper, the guy came up at him fast and wiped his legs away," said Lions manager Kenny Jackett, whose side are hovering perilously close to the drop zone.

"Too many results are going against us and conceding so many goals is giving us a mountain to climb.

"We need 21 points from the 17 games remaining to get us to 50 points and that is our aim."