Son Heung-min admitted talk was cheap after Tottenham were routed at Leicester.
The Foxes thumped Spurs 4-1 in the Premier League on Saturday in a damaging blow to their Champions League hopes.
Rodrigo Bentancur grabbed a first-half opener but goals from Nampalys Mendy, James Maddison, Kelechi Iheanacho and Harvey Barnes left Tottenham fifth in the Premier League.
Spurs go to AC Milan for the first leg of their Champions League last-16 tie on Tuesday and Son knows actions speak louder than words.
“I wouldn’t say we are confident, but words are not enough. We just have to go there and show on the pitch, that’s the most important thing,” said the forward.
“I can stand here and speak all day but the most important thing is on the pitch. We have to be as a unit and we have to be all together in the same way.
“Of course, it will be really tough, don’t get me wrong. We have to be more than ready, more than 100 per cent.
“We have only a few more days so we have to recover well, eat well, sleep well and go there and give it absolutely everything to achieve our aim.
“You learn more in a bad performance than in a good one. The performance was really poor and the fans deserve more than they received.
“We are playing in the Champions League on Tuesday, this was everyone’s dream and we wanted to be in this position last year.
“This could be the most important game because it’s a knockout stage so we have to bounce back stronger than ever. This will be a very important game.
“This could be the biggest lesson for us and this lesson should not be happening in Milan.”
Leicester secured back-to-back Premier League wins and scored four for the second-successive game with Maddison given the captaincy for the first time as Youri Tielemans was injured.
“The gaffer actually text me in the morning,” he said.
“He said: ‘Make sure you do a few press-ups today because you’re going to have the armband on’. Youri’s got bigger biceps than me!
“I see myself as the captain of this team without the armband.
“I’m 26 now and I’m one of the most experienced players, especially in the Premier League in the group we’ve got at the minute, so I do it anyway.
“Most weeks I’m doing that in the warm-up and in the changing room, getting the lads going.
“It’s something I feel I have a responsibility to do as one of the more senior players, whether I have the armband or not.”