While Falkirk had their chances, the Terrors created so many that they could have won a handful of games.
It began in the third minute with a great effort from Jon Daly which was ruled offside.
Paul Dixon had fired in a great cross for Warren Feeney to flick the ball onto the bar and Daly to knock in the rebound, but it was Feeney who had been marginally flagged offside.
With the United midfield dominant, the pressure built up and it was only a matter of time before the opening goal would arrive.
It duly did in the 21st minute courtesy of Scott Robertson.
A superb ball from Dixon gave Feeney space to dash into the box and cut it back for the midfielder to run in and take advantage of a weak clearance, smacking the ball low from 15 yards
With United in full flow, the Bairns almost grabbed an equaliser in the 29th minute with a great move ending with Steve Lovell almost rounding the keeper but seeing the ball run away from him as Lukasz Zaluska forced him wide.
This gave the visitors some encouragement and Scott Arfield really should have found the back of the net in the 37th minute with a free shot from 10 yards.
Falkirk continued to create the chances with a fabulous one-handed stop from Zaluska in the 49th minute
But the best chance of the game fell to Daly, who missed a glorious chance in the 55th minute.
Feeney teed it nicely up for him by laying the ball on a plate, but the striker blasted over the open goal from 12 yards.
Then Feeney missed another easy header two minutes later as United tried to seal the game.
United fans and players alike were furious in the 68th minute when they were denied a penalty by rookie referee Chris Boyle.
Incensed, United lost their concentration and a few minutes later Arfield hit the inside of the post with a 12-yard strike.
With Darren Barr being red carded in the 82nd minute, chances continued to fall for the hosts, but there were to be no more Christmas cheer for the Tannadice faithful.