Despite taking an early lead through Demi Akarakiri's 10th-minute goal, Everton trailed for most of the second half before Welch's late intervention. The 17-year-old Akarakiri had fired from close range to score his second goal in his last two matches.
Southampton equalized and then took what looked like a decisive lead, only for Welch to head home a Francis Gomez corner in added time to earn a valuable point for the traveling young blues.