GARETH SOUTHGATE admits he will not be able to fit all of England’s attacking players into his side to face Croatia in the opening game of the European Championships, and insists he has to ensure he has the right balance when his side’s Group D campaign begins on Sunday.

Southgate’s side completed their preparations for the Euros at Middlesbrough’s Riverside Stadium this evening, with Marcus Rashford’s second-half penalty securing a 1-0 win over Romania.

While James Ward-Prowse pressed his claims to replace the injured Trent Alexander-Arnold – Southgate will announce who has promoted to his 26-man squad tomorrow – Jack Grealish also caught the eye with a series of effective dribbles.

Grealish is competing against the likes of Phil Foden and Mason Mount for a starting spot against Croatia, with Rashford, Raheem Sterling and Jadon Sancho also in the mix for a place in the side that will line up at Wembley.

“It’s definitely going to be difficult to fit all of them in,” said Southgate, who saw Wearsider Jordan Henderson miss a second-half spot-kick in today's game.

"It’s got to be balanced for any team, and there’s always a numbers game to be played. In the last couple of games, we’ve got four attacking players into the team. Obviously, different teams have different ways of doing that. Chelsea just won a Champions League with only three really.

“We’ve got to get the right balance, find players who are in form, and find players who we think are out best players for different games. But we’re going to need them all.

"Players who start game one, there’ll be changes during the game. I was talking just now about 1998 (in the World Cup in France), and David Beckham didn’t start the first game. Michael Owen didn’t. But by the end of the tournament, Michael Owen was a superstar. Those changes happen.”

Ward-Prowse’s set-pieces were a key feature of today’s game, and the Southampton midfielder finds himself battling against Jesse Lingard, Ben Godfrey and Ben White for the final place in England’s squad.

“James’ professionalism and approach all this week, given the disappointment of having been left out, have been absolutely first class,” said Southgate.

“The decision won’t necessarily be about the performances today, it might be about where I feel I need the most cover because I couldn’t be happier with the way the players who were left out approached things.”

The start of today’s game was once again blighted by a number of England supporters booing as the players took the knee.

The boos were accompanied by a loud round of applause, with Southgate adamant he and his squad will not be changing their approach.

“Sadly, I think I expected what happened to happen,” he said. “We’ve accepted that as a group. It’s not going to stop what we’re doing and what we believe. We’re going to have to live with that.”