Southampton exited the FA Cup after suffering a comprehensive defeat against Arsenal at St Mary’s.
Danny Welbeck — making his first start on return from injury — struck twice and Theo Walcott scored a hat-trick for Arsenal.
Southampton, who reached the EFL Cup final on Wednesday, made wholesale changes, but Claude Puel’s young side struggled to manufacture any clear-cut chances and had just two shots on target.
Arsenal boss Arsene Wenger, meanwhile, watched on from the stands serving the first of his four game touchline ban after accepting a misconduct charge.
The visitors dominated the opening exchanges and Welbeck duly gave Arsenal a 1-0 lead on 15 minutes when he chipped the ball over the keeper and into the net via way of the crossbar.
Welbeck then added a second seven minutes later as he latched onto Alex Oxlade-Chamberlain’s pinpoint pass over the defence.
Southampton’s best chance fell to Shane Long, whose goal at Anfield secured a place at Wembley, but the striker only forced a 26th-minute save at the near post.
Compounded by a turnover from Jack Stephens that struck his own teammate, Theo Walcott turned in a third after Welbeck’s cutback allowed the former Southampton man to fire into an empty net.
Harry Lewis prevented the score from growing further by denying Hector Bellerin’s shortly after the restart, but Walcott netted twice in the final 20 minutes.
Southampton: Lewis, McQueen, Gardos, Stephens, Martina, Reed, Clasie, Hojbjerg, Sims, Isgrove (Tadic 64), Long (Redmond 64).
Unused subs: Taylor (GK), Betrand, Yoshida, Davis, Romeu.
Arsenal: Ospina, Gibbs, Holding, Mustafi, Bellerin, Oxlade-Chamberlain, Maitland-Niles, Lucas, Reine-Adelaide (Iwobi 72), Walcott, Welbeck (Sanchez 65)
Unused subs: Martinez (GK), Jenkinson, Mertesacker, Gabriel, Monreal.
Goals: Welbeck (15, 22), Walcott (36, 69, 84).