Sam Gallagher and Ollie Cook were each on target as Saints U21s took a point off league leaders Sunderland at the Stadium of Light.
All four goals arrived in the second half with Saints twice taking the lead before being pegged back, with the final two goals of the game coming inside the last five minutes of action, with Cook heading Saints into a 2-1 lead before Luke Molyneux crashed home a late leveller.
After a goalless first half, Saints took the lead nine minutes into the second 45 when Gallagher reacted quickest to turn home inside the area after Olufela Olomola’s shot had been saved.
Sunderland equalised with seven minutes remaining when George Honeyman beat Gazzaniga with a low strike into the bottom right corner, but the final flurry where Saints retook the lead before being brought back level again late on made it a frantic finish.
Ahead of kick-off Saints made three changes to the team that beat Liverpool, with Jake Vokins, Olufela Olomola and Dominic Gape all returning to the side, with Gape taking the armband.
It was a lively encounter from the start as the visitors worked hard to contain an attack-minded home side in the opening exchanges.
Sunderland had the better of the chances in the opening 45 minutes, with George Honeyman shooting into the side netting from the right after creating an opening for himself inside the area.
And, on 18 minutes Carl Lawson drilled a low shot wide of the far post after getting the better of Vokins.
While Saints were restricted with clear opportunities, they were comfortable in possession when they had the ball, and they enjoyed a good, long spell of possession using the full width of the surface.
Goalkeeper Paulo Gazzaniga was called upon in the 28th minute to deny Thomas Beadling’s well-struck free kick from the edge of the area, with the Argentine producing a strong punch away to his right.
With no goals in the first half, the two teams were unchanged for the second 45 and the action picked up from where it left off, as Saints continued with their pressing, possession-based game.
The higher level of intensity from the visitors saw them threaten their opponents much more in the early stages with Sam Gallagher unfortunate not to beat goalkeeper Maksymilian Stryjek to the ball in one move, while Gallagher and Olomola’s link-up looked promising.
And that bore fruit on 54 minutes with the opening goal of the game. Olomola pounced on a loose pass from Beadling to take aim from distance, and while Stryjek made a good save, the rebound fell invitingly to Gallagher, who struck home into the bottom left corner for 1-0.
Gallagher could have had a second on 63 minutes when he powered his way through into the area, but his low shot was saved well by Stryjek with his feet.
Reed was next to fire a shot towards goal, though his strike went over, but he was also pivotal at the other end to clear the danger as Sunderland came back into it.
At the other end Mandron get a header on target from a corner which Gazzaniga pushed away, before the glovesman was also alert to keep out Honeyman’s strike from the edge of the box.
Both teams had further opportunities in the closing stages with Lawson firing narrowly over at one end, before Josh Sims struck a low shot wide.
And Sunderland dug deep to equalise with seven minutes remaining when Honeyman got in on the left side of the area to curl a low shot past Gazzaniga for 1-1.
As the game entered the closing stages, Mandron’s header was cleared off the line by a combination of Olomola and Gazzaniga.
Saints then thought they’d won it when Ollie Cook headed in at the far post from Alfie Jones’s nod back across the area, but Sunderland’s double substitution spoiled the party late on with Luke Molyneux turning in Rees Greenwood’s low cross at the far post for 2-2.
Sunderland U21s (4-3-3): Maksymilian Stryjek, Joshua Robson (Luke Molyneux 87), Thomas Robson, Liam Agnew (c), George Brady, Thomas Beadling, Carl Lawson, Daniel Wright (Andrew Nelson 87), Mikael Mandron, George Honeyman, Rees Greenwood. Unused substitutes: James Talbot (GK), Denver Hume, Daniel Casey
Goals: Honeyman (83), Molyneux (89)
Southampton U21s (4-2-3-1): Paulo Gazzaniga; Dominic Gape (c), Alfie Jones, Ollie Cook, Jake Vokins; Harrison Reed, Armani Little; Jake Hesketh, Josh Sims, Olufela Olomola; Sam Gallagher. Unused substitutes: Harry Lewis (GK), Richard Bakary, Ben Rowthorn, Tyreke Johnson, Dan N’Lundulu
Goals: Gallagher (54), Cook (87)