The UEFA Euro 2020 is back in action with another round of matches this weekend as England lock horns with Croatia in a crucial Group D encounter at the Wembley Stadium on Sunday. Both teams have excellent players in their ranks and will want to lay down a marker this weekend.Croatia are in a period of transition at the moment and will have to work hard to revive their fortunes ahead of a difficult schedule. The Balkan giants suffered a 1-0 defeat at the hands of Belgium earlier this week and will need to bounce back in this match.England, on the other hand, have been impressive under Gareth Southgate and have assembled a formidable squad for Euro 2020. The Three Lions have lethal forwards in their ranks and have a point to prove against Croatia.🗣️ "I think it's time for the country to unite, full stop. That's how I see it."Gareth Southgate is calling for unity ahead of England's opening game against Croatia.#bbceuro2020 #ENG— BBC Sport (@BBCSport) June 12, 2021England look to avenge World Cup semi-final defeat against CroatiaEngland were well on their way to a World Cup final in 2018 before an in-form Croatia outfit derailed their hopes in the semi-finals. The Croatians have aged as a squad over the past two years, however, and will find it difficult to keep a new-look England side at bay in this fixture.Gareth Southgate has selected some of the brightest young talents in England for Euro 2020 and the likes of Mason Mount and Phil Foden will be looking to make a mark. In this article, we look at five key battles that could determine the outcome of England's first UEFA Euro 2020 match.#5 Ante Rebic vs Luke ShawRebic has been excellent for AC MilanIn a Serie A campaign that was supposed to be dominated by the evergreen Zlatan Ibrahimovic, AC Milan's Ante Rebic has held his own and has pulled off some excellent results for the Rossoneri. The Croatian forward has managed 11 goals and four assists in the Serie A and is in the form of his life.Croatia have suffered in the final third in recent weeks and will need to get the best out of their attacking options at Euro 2020. England's defence will present a litmus test, however, with left-back Luke Shaw taking on Ante Rebic this weekend.After a series of struggles with his fitness, the Manchester United full-back has come into his own this season and has been one of his club's best players. Rebic has plenty of pace at his disposal but will likely meet his match at UEFA Euro 2020 in England's Luke Shaw.#4 Jack Grealish vs Sime VrsaljkoGrealish is an important player for EnglandJack Grealish is only 25 years of age and has already had an eventful career. The charismatic forward is already a living legend at Aston Villa and will finally be given an opportunity to shine on the big stage with England at UEFA Euro 2020.Grealish has registered 16 goal contributions in the Premier League and can be virtually unplayable on his day. The Aston Villa man transforms England's attack into a well-rounded unit and will look to replicate his Premier League form in the tournament.Jose Mourinho has likened Jack Grealish to Luis Figo 👀 pic.twitter.com/NUmWlnaRDY— ESPN FC (@ESPNFC) June 11, 2021Sime Vrsaljko has had to make do with a diminished role at Atletico Madrid after an injury-ridden year. The Croatia defender has plenty of experience, however, and will be up to a stern challenge as his side takes on England's forward line.Also Read: Fabrizio Romano's Transfer Roundup: Update on Manchester United's pursuit of Jadon Sancho, Chelsea's plans for Hakimi and more