A late mistake from Tomas Repka cruelly helped to deny Hammers all three points against league leaders Norwich City in a thrilling encounter at Carrow Road.
The Czech defender's weak back-header 14 minutes from time allowed Darren Huckerby to snatch a point for the hosts after Marlon Harewood's stunning strike on the hour had looked like giving Alan Pardew's men a fantastic victory.
And things didn't get any better late on, as Matty Etherington was controversially sent off in the closing stages for failing to place the ball correctly for a corner-kick - his second bookable offence.
It was a sour end to a fantastic afternoon of entertainment in east Anglia, as the two rivals produced a committed, attacking and exciting display that proved just why both are tipped as strong favourites to end the season as promotion winners.
With the return of no fewer than six players - ineligible for the FA Cup fifth round clash at Fulham last week - Pardew had been able to make changes to his starting line-up. Bobby Zamora came in for his first start in a Hammers shirt, while Jon Harley returned to the left-back role and Nigel Reo-Coker replaced Kevin Horlock in the centre of midfield.
However, such are the resources available to the Hammers boss at present that Horlock and Anton Ferdinand - another star of the draw at Loftus Road - were not even consoled with a place on the substitutes' bench. The returning Andy Melville, Adam Nowland and Jobi McAnuff, along with Brian Deane and new loan signing Pavel Srnicek filled those places.
The 24,000 capacity crowd at a freezing Carrow Road had been warmed up before kick-off when four legend who wore both claret and blue and yellow and green turned up to open Norwich's brand new South Stand. Graham Paddon, John Bond, Martin Peters and special guest of the day, Ken Brown, were given a rapturous reception from both sets of supporters.
With 2,000 travelling Hammers fans offering a rousing rendition of Bubbles and a buoyant home crowd reminding everyone of their current status as the Division One leaders, the scene was set for an action-packed afternoon - and from the first minute Hammers failed to disappoint.
Just 90 seconds had passed when Zamora was set free by Connolly's neat flick. However, as he cut in from the right, the striker screwed his shot across the face of goal and a defender's boot deflected the ball agonisingly beyond the reach of Etherington.
From the resulting corner, Zamora again found himself on the end of a shooting chance as the ball dropped to him six yards out but a defender hacked off the line for another corner. Amazingly, Carrick's kick set up a third chance, as the ball was only cleared to the edge of the box, where Harley shot inches wide.
Quite a start, and more was to follow, as first Harewood and then Etherington fired in dangerous low crosses that Zamora was just inches away from making contact with, while Carrick and Reo-Coker both dragged shots wide from good positions.
At the other end, Huckerby was Norwich's main attacking threat - his pace and power causing problems for Dailly and Repka, but the Canaries' best chances fell to left-winger Jim Brennan, who twice shot straight at Bywater from 12 yards out.
The Hammers keeper had to be alert again two minutes into the second half, when he kept out McVeigh's looping header after Huckerby had found space to cross on the left, and when Bywater was beaten by the Norwich striker a few minutes later, Christian Dailly was on hand to superbly clear his goalbound effort.
After weathering that early storm, it was the visitors who again created the better chances as the game progressed. Etherington's deep cross was met by a sweet - but unfortunately inaccurate - volley from Connolly, before Harewood gave his side the lead in magnificent style.
A searching pass from Mullins found Zamora, whose clever flick released the former Nottingham Forest hit-man. Advancing towards the penalty area, Harewood ignored the run of Connolly and unleashed a stunning right-foot shot that gave Norwich keeper Robert Green no chance on its way to the top corner.
Zamora wasted a decent chance to double the lead two minutes later but, with Carrick and Reo-Coker enjoying the lion share of possession and Repka and Dailly looking solid at the back, Hammers were firmly in the driving seat and well on their way to closing the gap on the league leaders.
With just 14 minutes remaining, though, Nigel Worthington's team got out of jail thanks to Repka's only error of the afternoon. A long, aimless ball forward appeared to hold no danger as he shaped to guide the ball back to Bywater, but the Czech hardman headed upwards rather than onwards and the pacy Huckerby raced on to round the goalkeeper and fire into the empty net.
It was hard luck on the Hammers defender, who up until then had been flawless, but Pardew's men again showed their fighting spirit to ensure that Norwich's resurgence didn't lead to further disappointment.
When Zamora forced a corner with just five minutes remaining, it seemed that the visitors might even restore their advantage. However, that hope all but disappeared as Hammers were reduced to 10 men in bizarre fashion.
The baying home crowd behind the corner flag alerted referee Mr Oliver to the fact that Etherington had placed the ball just outside of the triangle. The Hammers winger responded to the official's orders by moving it back but, with the Canaries fans still claiming an injustice, Oliver moved closer to ensure the winger followed the letter of the law.
Without warning - or any attempt to check that the ball was actually placed illegally, the man in black blew his whistle and marched over to brandish the yellow card - Etherington's second after an earlier foul on McVeigh.
As his team-mates voiced their anger at the decision, a bemused Etherington walked off shaking his head and, while there may not have been enough time left for it to affect the result today, the former Spurs man will be sorely missed when he serves a one-match ban in a couple of weeks.
An angry Alan Pardew made his views clear to the referee at the final whistle but refused to let the incident take away from another tremendous performance on the road.
"The sending-off was ridiculous," he said afterwards. "Matt didn't really understand what the problem was and I thought the referee should have been stronger and not bowed to the pressure from the crowd.
"I told him afterwards that he had been weak and cost me a player, and we will miss Matt for a match now - he is a very important player to me.
"I am also disappointed that we didn't take all three points - because I felt we deserved them. There were some outstanding performances again today and we dominated for most of the game.
"Marlon's goal was a great strike and it was just a shame that Tomas made a mistake for their goal - he had been superb up until then. It's a blow, but we will keep battling game after game, and we have proved today that we are good enough to get in there at the end of the season."
by Danny Francis