Watford climbed into the Championship automatic promotion places despite being held to a goalless stalemate by draw specialists Millwall at The Den.
The Hornets had the better of an entertaining first half as Tom Cleverley's free-kick was headed against his own post by home defender Shaun Hutchinson and Bartosz Bialkowski saved Ismaila Sarr's shot with his legs.
But Jake Cooper twice came close to giving Gary Rowett's Lions an interval lead, first heading against the woodwork before seeing another header ruled out for offside moments later.
The second half was less of an event - Watford coming closest when Nathaniel Chalobah's 25-yard strike was beaten away by Bialkowski, who then tipped Troy Deeney's rebound wide.