Matthew Smith scored a penalty winner after Daniel Barden had saved from the spot as our under-18s secured a crucial three points at Southampton.
Our youngsters are now five points clear of the third-placed Saints, and 12 points adrift of leaders Chelsea with two games in hand going into the final three games of the season.
Kwame Ampadu made 11 changes to the side that booked a place in the FA Youth Cup final on Monday, but Smith and Trae Coyle - who came off the bench during our semi-final win over Blackpool - both started on the south coast.
Schoolboys Matthew Dennis, Miguel Azeez, Ben Cottrell and Armstrong Okoflex also started for our youthful side at Staplewood, and faced a tough test against an experienced Southampton side which included recent Premier League debutant Michael Obafemi.
The hosts started the stronger side, too, and had an early opportunity to open the scoring from the penalty spot in the first half. Fortunately, Barden was able to react well to make a smart stop from Jonathan Afolabi.
We improved after half-time and claimed our reward from the spot. Coyle was brought down by goalkeeper Adam Parkes, and Smith stepped up to send the Saints stopper the wrong way.
Barden had to make a number of fine saves throughout to preserve our clean sheet, while substitute Stan Flaherty missed the chance to double our advantage late on.
Ultimately, it would not matter. Our young backline stood firm to keep out wave after wave of Southampton attacks to all but secure second spot in the Under-18s Premier League South.
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