The frontman returned to the starting line-up after sitting out United's Boxing Day defeat at Liverpool - and responded by scoring with a trademark header just before the half-hour mark.

But substitute Abdoulaye Doucouré's 82nd-minute header earned the home side a point. 

Watford started the day in tenth place and threatened early on through former Barcelona winger Gerard Deulofeu, who was denied by the outstretched leg of Martin Dúbravka in the 16th minute - four minutes after Paul Dummett had slid in to steal the ball just as he was about to shoot from eight yards out.

But United grew into the game and took the lead in the 29th minute, as Rondón finished off a fine team move. Christian Atsu's clever turn took him away from two defenders and he played the ball out to Matt Ritchie on the left. Ritchie's cross was begging to be headed home and Rondón obliged. 

He had the ball in the net again soon afterwards, but was flagged offside as he connected with Ayoze Pérez's centre, and Watford ended the half on top as Isaac Success tested Dúbravka in the 43rd minute before Federico Fernández thwarted the same player with a last-ditch tackle just before the break.

In the 51st minute, another Ritchie delivery - this time from a left-wing corner - found Rondón, but the number nine couldn't keep his header down. 

Ritchie saw a 71st-minute drive from 20 yards fielded by Ben Foster then at the other end, Roberto Pereyra's free-kick was blocked by the Newcastle wall. In the 76th minute, Daryl Janmaat's cross was met by substitute Troy Deeney, but his header was too close to Dúbravka.

But then came the late sting from the Hornets, as Doucouré guided Deulofeu's cross home. DeAndre Yedlin came close to restoring United's advantage, while Success saw an effort saved by Dúbravka in stoppage time, but it finished all square.