Watford head coach Vladimir Ivic saluted his goalkeeper Daniel Bachmann after the Austrian's brilliant performance in their penalty shoot-out victory over Oxford at the Kassam Stadium.
Bachmann pulled off several fine saves in normal time as sub Ken Sema equalised in the 89th minute for the Hornets to make it 1-1 and take the game to penalties.
And in the shoot-out, Bachmann brilliantly saved all three of Oxford's spot kicks to send the Championship side into the third round where they visit Newport.
Ivic said: "It was amazing goalkeeping, not just the penalties - all game he was quality. He had a fantastic evening."
The Hornets also showed character in fighting back from Rob Hall's fine strike on 26 minutes for the League One side who had some great chances to put the game out of the visitors' reach.
They were down to 10 men for the last 20 minutes after Marc Navarro limped off when all the substitutions had been made.
Ivic added: "We had a lot of new players out there and we knew it was not going to be easy.
"We were starting with a lot of new boys who were playing for the first team for the first time. And some had not played in a match for a number of months - some since February.
"You cannot expect them to give their best performances from the start. But game by game they will get physically stronger and better."
New Croatia striker Stipe Perica squandered two good chances, but put away the tie-clinching penalty in the spot kick.
"Tonight there were no goals for Perica, but the goals will come for him," Ivic said.
"I believe Oxford were better in the first 45 minutes, but in the second half we had good shape and we started to play, and some substitutions changed the momentum.
"Our target was to move on to the next stage of the competition. And we have done that.
"And there will be good lessons for us from this game."
Oxford boss Karl Robinson said: "We were excellent. Yes, our penalty shoot-out run has ended but I was very proud of the team.
"We had a lot of players who were in uncomfortable positions, and when you think that's a Premier League budget we were up against.
"The one grumble is that there were three or four chances that we didn't take that we probably should have done.
"There was a fluidity to our play which was very pleasing, as were some of the experimental things I tried out, which worked.
"Being highly critical, we've got to put teams to bed when we are on top as we were.
"But I go away from here in a good mood because a lot of things were very encouraging for me.
"The one big concern is the injury to John Mousinho which doesn't look good.
"It appears to be the ligament in his knee which he has injured before, but it will need proper analysis. But we are lacking in defenders now.
"Their keeper was different class tonight. I thought he was their best player in the 90 minutes."