ESPN breaks down everything you need to know, including where the game will be won or lost, the key players, and predictions as to who will go through.
Leicester City vs. Southampton (Sunday, 1:30pm ET on ESPN+)
Overview: Both teams come into this off the back of painful defeats, but with different prospects and aims for the rest of the season. Brendan Rodgers' Leicester City are still firmly in the mix for a Champions League spot despite losing 3-2 at the weekend to West Ham United. But they have also had to contend with off-field strife in the last week, with three of their players stood down for the trip to West Ham due to COVID-19 protocol breaches. Hamza Choudhury and James Maddison missed out on that match after reports they attended a party at Ayoze Perez's house. The trio are back in the mix for this weekend, but it was a distraction Rodgers could have done without.
Southampton are an unpredictable quantity at the moment. Ralph Hasenhuttl's side lost 3-0 to West Brom at the weekend, meaning they have lost 11 of their last 14 top-flight matches. Hasenhuttl warned his players if they play against Leicester as they did against WBA, they have "no chance" of getting through after what he labelled a "non-performance" against Sam Allardyce's side.
Leicester booked their spot in the final four thanks to a 2-1 win over Manchester United, while Southampton eased past Bournemouth 3-1. This match has the bonus of being played in front of 4,000 local Wembley residents as one of the government's test events to get bigger crowds back this summer.
Where Leicester City will win or lose: Leicester have lost two from two since the international break, and have lacked the intensity which saw them beat United in the quarterfinal. They are finding themselves in solid positions on the field, but also have looked vulnerable at the back.
They are used to dominating possession and territory and will likely enjoy plenty of time on the ball this weekend. They also have one of the in-form players in the Premier League at the moment, with Kelechi Iheanacho on a goal-scoring run of nine in six matches. The omens are good for the Foxes -- they have never lost three on the bounce under Rodgers -- but they need the whole team to come together after a tough week on and off the field as they contest the club's first FA Cup semifinal since 1982.
Where Southampton will win or lose: Southampton's 2021 has been poor. That free-flowing, rock'n'roll gegenpressing football we saw in the latter stages of 2020 has been replaced by erratic and frustrating performances in the league. But their FA Cup form has been the outlier. They were magnificent against Bournemouth in the quarterfinals -- with Nathan Redmond outstanding -- and they hoped to ride that wave into Sunday's semifinal, only for WBA to bring them crashing back down to earth.
Self-confidence could be a big issue come Sunday, given their recent form, and while Che Adams and James Ward-Prowse have kept their form at a consistently high level, too many of their teammates have experienced a drop since the New Year. If Southampton re-find their mid-season best (like we saw in their win over Liverpool in January) then Danny Ings (whose long-term future is starting to get more airtime at St Mary's given his contract is up in 2022), Adams and Ward-Prowse can cause Leicester some headaches. That said, they will need a full team performance if they are to get through to their first FA Cup final since 2003.
Key players: Iheanacho is playing superbly at the moment for Leicester, and his two goals helped them to their 3-1 win over United in the quarterfinals. Youri Tielemans is excellent in the middle of the park, and he dovetails nicely with Wilfred Ndidi so expect them to see plenty of the ball on Sunday. They will likely be without Harvey Barnes for the weekend but should have their disciplined trio back in the mix. Also keep an eye on Wesley Fofana at the back, as the young French defender has been one of the players of the season and seen his stock skyrocket.
Ward-Prowse's set-piece prowess is a key weapon in Southampton's arsenal, and he leads the Premier League with four goals from free kicks this term. He's the focal point of their side and has contributed the most assists (five) in the league, has the second most recoveries (234) and has attempted the sixth-most passes (2022 in the Premier League). Ings has nine goals for the season so don't forget about him, while Adams is also impressing up front. Finally, Redmond has found some form with three in three while centre-backs Jan Bednarek and Jannik Vestergaard are solid.
Prediction: Leicester City should have too much for the Saints and book a place in their first FA Cup final since 1969. They'll need to come together after a difficult week but will live up to their tag as pre-match favourites.