England captain Wayne Rooney has admitted that his side must improve from their performance against Portugal on Thursday if they are to succeed at this summer's European Championships.

The Three Lions needed a late winner from Chris Smalling to edge to victory over their visitors, who were without Cristiano Ronaldo and had to play the majority of the match with 10 men following Bruno Alves's head-high kick on Harry Kane.

Kane bounced straight back up after the challenge and tried to carry on, raising concerns that England's honesty could be a weakness that is exploited by other teams, but Rooney played down the importance of needing to be more streetwise.

"If you're looking at that, then I think we'd be struggling if we're relying on that to win and go far in the tournament. It can be a small margin which can benefit you, but the other things we're doing and planning completely outweigh that. That's a tiny thing you can do better. [We need to] more understand the game and manage the game better. It's normal: that comes with experience," he told reporters.

"Whether it's stopping a quick free kick, or - I'm not saying anything bad about foreign players - but they do it naturally better in terms of staying on the ground a bit longer, and almost making a decision for the referee which we haven't been brought up to do. It's a big difference for us to do that.

"Harry had seen his opportunity, I think if the referee had played on, we might have went on and scored. In the past we've always been an honest team, an honest country. We can play better (than we did against Portugal), we can move the ball quicker. (We've had) three wins coming into the tournament but I still feel we have to (do) better."

Rooney has also labelled England's opening match against Russia in Marseille on June 11 as a "massive" game.