John Terry insists England can improve by "another 20 or 30%" ahead of the World Cup finals.
England qualified for South Africa 2010 with two games to spare and finish their campaign with a match against Belarus in front of their home fans at Wembley on Wednesday night.
The Three Lions failed to qualify for Euro 2008 and although standards have improved dramatically under new manager Fabio Capello, who had a 100% record in qualifying until Saturday's defeat in Ukraine, Terry insists the team are far from the finished article.
"We've come a long way but can still get better all over the field both collectively and individually," the England captain said. "But we've still got another 20 or 30% to improve.
"We've got huge improvements to make all over the field, in defence and going forward and I'm sure the manager in the next few games will try different things.
"When you feel that, you feel you can go up another level. That confidence is there. We do feel quietly confident. The improvements are there all over the squad and the manager has been a massive part of that."
The FA have already penned in four friendlies before the World Cup gets under way on June 11 and Terry believes there will be no let up in the high standards of Capello.
The Chelsea defender said: "Every day in training, if you have a bad session, the manager is on top of you - asking you if you're tired or what's wrong? You can't have a bad session, a bad game for your club - and for those players on the fringe, it's highlighted a little bit.
"The lads who have been in there have been playing really well - so those on the fringe know they have one chance, and if they don't take it they might be back on the bench. It maybe puts them under a little bit of pressure, but that drive that everyone is showing to fight for their place is a good hunger to have in the squad."
Terry confirms Capello demanded his players show a greater work-rate from the moment he took charge 22 months ago and uses DVD sessions to highlight players mistakes.
He said: "Collectively, when the manager first came in we watched a few videos of the first few games - and he wanted the players to work a lot harder.
"If a defender goes forward then it's a sprint and not a jog back to get into position. That's very Italian-minded. The players are really working hard for each other. It really does make a difference if you can sprint back and help your team-mates."
Terry admits he has had the 'red-beam' treatment "a couple" of times.
"You know the minute you've made your mistake, or a misplaced pass, and you're thinking 'please don't stop the DVD now'," he said. "Then he stops it and gets his red beam and flashes it at you! It's definitely in your mind (during the game itself). You get used to it, and now it's cemented in. Everyone's naturally working harder now."