Walter Mazzarri hopes the signings of Younes Kaboul and Roberto Pereyra can help Watford improve in the crucial moments of matches after Saturday's 2-1 defeat to Chelsea.
The duo agreed moves to Vicarage Road on Friday and were presented to the home faithful prior to kick-off, but they then watched on as Watford threw away a one-goal lead.
Etienne Capoue fired the Hornets ahead just before the hour with his second goal in as many games, but Chelsea scored twice in the final 10 minutes to take the points.
Goals from Michy Batshuayi and Diego Costa consigned Mazzarri's side to defeat, leaving the Italian hoping new faces can improve their fortunes.
"I am happy for how we played for 70-80 minutes because we played very well, but I am not happy with the result," he is quoted as saying by BBC Sport.
"What can I think? They scored two goals that could have been avoided. We are a team that still has room to grow and there is margin for improvement.
"The new players can help us a lot and they can help us improve as a team. We played very well, so the way we played in the first half, we could have scored twice."