The Three Lions know that a victory at the Liberty Stadium will put them on the verge of winning the group, with only two more fixtures to come after this.
But head coach Southgate knows it won’t be easy for his side, with memories of March’s game in Derby still relatively fresh for all concerned.
Wales U21s v England U21s
UEFA European U21 Championship
Group One qualifier
7.30pm, Monday 19 May 2014
Liberty Stadium, Swansea City FC
Live on Sky Sports
It took a single goal from Norwich City’s Nathan Redmond to win that game and Southgate believes Monday’s match will be their hardest to date, with Geraint Williams' side proving hard to break down at the iPro Stadium.
"Wales will be a really good challenge for us," he revealed.
"They showed enough in the last game in terms of their speed on the counter attack and were resilient defensively.
"They’ve got some good footballers, some of who have had good spells with their clubs since the game in March, so we’re under no illusions that this will be a big test and probably our toughest game in the group.
"We’ll have to be at our very best and I’m looking forward to seeing one or two new lads come in and take that challenge."
Southgate has a squad of 24 to pick from for the game, with the Toulon Tournament to come later in the week for 20 of those players with Danny Ings, Tom Ince, Jesse Lingard and Carl Jenkinson only available for Monday's match.
Watch slo-mo highlights of England's 1-0 win over Wales in March
But he’s been pleased with the way the new group has gelled together since meeting up on Thursday and training at St. George’s Park before making the journey to South Wales on Sunday afternoon.
"We’re looking forward to this, we’ve got some new players coming in who we wanted to look at and it’s an opportunity for them over the next few weeks," he added.
"That’s the challenge for all of them, to show what they can do against each other in training and the standard has been good.
"It’s been a good group of players all season and we’d obviously like to finish the season on a high with the game in Wales before we head out to Toulon."
Monday’s match kicks-off at the Liberty Stadium at 7.30pm and will be shown live on Sky Sports.
