"Galls is a quality player. I think that's 11 goals he's got for the season and with the goals comes confidence.
"You saw that out there, but what really pleased me is when Watford got it back to 1-1 we showed the character to go on and win the game.
"That may not have happened a few weeks ago."
Argyle followed up their first win of 2009, 1-0 at leaders Wolves on Saturday, with their first home win of the year.
"It's been long overdue but I think we were worth it tonight. I did not think we played as well in the second half but you have to give credit to Watford, they improved in the second half.
"Now we have got a biggie at home to Reading on Saturday, and they won tonight and the teams down with us - like Southampton and Norwich - have won so there's still plenty to play for and I won't be happy until we are past the 50-point mark by some way."
Watford boss Brendan Rodgers.
"I am disappointed with the result.
"We made two mistakes tonight and to be fair they are probably the first mistakes we have made in about five games.
"I was happy with the second half, with their character and it was a terrific goal by Tommy Smith.
"We went on the front foot then.
"As I said we made two mistakes and got punished tonight, so congratulations to Plymouth.
"I made some changes tonight. I just feel that we have got a load of games coming up and the idea was to give Tommy and a few of the others a rest tonight but know the group was still strong and allows to keep the intensity going.
"Tommy came on and he was great and scored an excellent goal.
"I trust the players, we just never got going first half and didn't get high enough up the pitch and I thought Plymouth played well first half."