Adam Masina's strike earned Watford victory over Nottingham Forest as a sixth win in seven Championship games sent the Hornets second.
Forest, who have now managed three goals in seven matches and are only eight points clear of third-bottom Rotherham United having played three games more, improved considerably after the interval.
Anthony Knockaert, Gaetan Bong and Cafu went close, before Cafu's fellow substitute Lyle Taylor had a goal rightly ruled out for offside.
But Watford stood firm and were good value for a win which took them three points clear of Brentford, whose game against Rotherham was postponed.