The Hoops play host to St Johnstone in the Scottish Communities League Cup, aiming to bounce back and book their place in the last four of the competition.
Watt hopes the quarter-final clash will allow Celtic to make amends after admitting everything went wrong at the weekend.
He said: "It's good to have another game. It's against St Johnstone who have beat us as well.
"Hopefully we can get one back on them and get past what happened at the weekend.
"The manager spoke to us but we know we weren't good enough and he knows we weren't good enough.
"We all know we were sloppy and could have played a lot better.
"The tempo wasn't high enough, we didn't press them, there were a lot of things.
"It was just one of those days and everybody contributed to how bad the team was.
"Everything we did wasn't right. Hopefully we can do better in this game."
The loss to Kilmarnock came just days after a last-gasp defeat to Barcelona in the Champions League, with the Nou Camp encounter earning Celtic plenty of plaudits if not the points.
Watt added: "The boys were brilliant in Europe and that just shows what they can do.
"We can't make excuses for Saturday's game. Everybody contributed.
"I came on and missed a chance that on another day would have been buried. But I can't look back on it and dwell on it."
Prior to Saturday's loss to Killie, Celtic's only defeats this term were against St Johnstone and Barca but Watt claims the desire to come out on top against Saints would be just as strong regardless of their last meeting.
He said: "We look at every game the same and we want to win it - even the Barcelona game.
"We can't treat anybody lightly and we can't respect anybody too much.
"St Johnstone will think we've got a point to prove but we've not, we just want to win the game like we want to win every other game in Scotland because we are seen as the best team in Scotland."
Saints boss Steve Lomas downplayed the significance of his side's 2-1 win on September 15, a result which sparked a seven-match unbeaten run ahead of the trip to Parkhead.
"It's a totally different game," Lomas said.
"It's about who performs on the night. We're under no illusions it will be very, very difficult.
"We're really looking forward to it. The boys always enjoy playing at Celtic. We're going to go there, give it a right go, given the size of the task."