Middlesbrough manager Kim Hellberg said spying on opposition training sessions would give a team a “massive advantage” after the Championship side drew the first leg of their play-off semi-final 0-0 at home to Southampton.

The English Football League charged Southampton with spying on Boro before each side took the first step in their post-season campaigns to reach the Premier League, with Tommy Conway striking a post as part of an utterly dominant first half for the hosts.

“It just doesn’t feel right,” Hellberg told Sky Sports of the accusations, which Southampton have acknowledged but not commented upon.

“It’s nothing against Southampton players, supporters or anything… they haven’t done anything. But in general, it’s not okay.”

Taylor Harwood-Bellis sent a late header against the crossbar for Saints, who finished fourth in the second tier and a place above Middlesbrough by a one-goal superiority.

The winners of the tie will face Millwall, who finished third, or Hull City, who came sixth, in a one-off decider at Wembley Stadium on May 23 to join the 2026/27 top flight.

The Lions and the Tigers drew 0-0 at the MKM Stadium on Friday.

Middlesbrough team vs Southampton

Middlesbrough starting XI: Sol Brynn, Luke Ayling, Dael Fry, Adilson Malanda, Callum Brittain, Aidan Morris, Riley McGree, Matt Targett, Morgan Whittaker, David Strelec, Tommy Conway

Middlesbrough substitutes: Alex Gilbert, Alan Browne, Sam Silvera, Leo Castledine, Sontje Hansen, Joe Wildsmith, Cruz Ibeh, Jeremy Sarmiento, Harley Hunt

Southampton team vs Middlesbrough

Southampton starting XI: Daniel Peretz, James Bree, Taylor Harwood-Bellis, Nathan Wood, Ryan Manning, Tom Fellows, Caspar Jander, Finn Azaz, Flynn Downes, Leo Scienza, Cyle Larin

Southampton substitutes: Ross Stewart, Joshua Quarshie, Cameron Archer, Samuel Edozie, Shea Charles, George Long, Kuryu Matsuki, Welington, Cameron Bragg

What’s next? Championship play off fixtures, schedule