Cesar Azpilicueta has admitted morale at Chelsea is low due to their three-match winless run.
Chelsea, since winning impressively at Atletico Madrid in the Champions League last month, have lost successive Premier League games to Manchester City and Crystal Palace.
They avoided defeat -- and a third straight loss for the first time under Antonio Conte -- when drawing 3-3 with Roma in the Champions League on Wednesday, but did throw away a two-goal lead at Stamford Bridge.
"The mood at the moment is not the best," Azpilicueta told the Evening Standard. "It's true that we are not in our best moment. We came into the game after two consecutive defeats in the Premier League.
"We had the game in our hands [against Roma] when we were 2-0 up, but we also had it lost when we were 3-2 down. We managed to get a point, we are top of the group and we will keep fighting.
"To come back into the game to get a point is big for the team, to show the character and that we won't give up. But the reality is that we have gone three games without a win and we will try to get back to winning ways on Saturday [against Watford]."
Chelsea lead Champions League Group C by two points from Roma ahead of the Oct. 31 fixture in Rome.
Eden Hazard wants a win there and early progression to the knockout stages.
Hazard scored his first Chelsea goals of the season with a brace on Wednesday and his first in the Champions League since March 2015.
He told Chelsea TV: "I think if we want to finish the job we need to win there. We know what to do. We want to finish the group stage as soon as possible and be the first team to be qualified."
Conte, meanwhile, hopes David Luiz will be fit to face Watford after sustaining a calf injury against Roma, rather than join N'Golo Kante, Victor Moses (both hamstring) and Danny Drinkwater (calf) in missing out. Tiemoue Bakayoko (groin) could also be a doubt.
Conte told Chelsea TV: "[Luiz] felt a bit of pain in his calf, but he should be OK for Saturday, I hope."