In a cracking advert for the second tier of English football, the Hornets produced 26 attempts on goal, but had to rely on Marlon King's ninth of the season to earn them a point after Clive Platt and Kevin Lisbie had more than cancelled out Adam Johnson's early opener.
However, King's equaliser could have been the winner because the ace marksman saw a penalty saved by Dean Gerken moments earlier, while Lee Williamson was also denied by the woodwork.
By the same token though, the U's would have taken all three points had it not been for a fantastic fingertip save from Richard Lee to push a Mark Yeates free-kick onto the crossbar.
The league leaders had earlier got off to a flyer, taking the lead inside two minutes with one of the softest goals they will score this season. Johnson received the ball back from a short corner and swung in a cross towards the near post which should have been meat and drink for Gerken.
However, the U's keeper was possibly put off by Bela Balogh diving in front of him with an attempted clearing header, only to fail to make contact and Gerken was unable to prevent the ball crossing the line.
However, Colchester clearly hadn't read a script that said comfortable home win and were back on terms after 19 minutes.
Kem Izzet's intelligent clipped pass from the left side of the penalty area cleared Jordan Stewart and Platt, coming in behind the Hornets' left-back, thundered a header against the woodwork. Platt then reacted first to the rebound, getting the ball under control, before firing a cross-shot across Lee to equalise.
If that surprised the Hornets, what happened less than 40 seconds after the restart must have left them stunned. Lisbie was left all alone on the right side of the 18-yard box to receive another astute pass from Izzet, and the former Charlton striker made no mistake, firing across Lee and inside the far post.
But a point was the very least the league leaders deserved for their attacking dominance. They should have got it when Johnson was barged over in the penalty area by Yeates, but King rather telegraphed his effort from 12 yards at Gerken.
However, rather than dwell on what might, or indeed should have been, the Watford striker responded to that personal setback in the best way possible.
A Tommy Smith cross from the right was half-cleared to Williamson, whose goalbound shot hit King, and the forward reacted to the bouncing ball by taking off and connecting with a bicycle kick that directed the ball back into the ground and up and wide of Gerken.