Two Harry Whitwell goals saw Albion's Under-21s turn their Premier League 2 game against Chelsea on its head to win 2-1 on Saturday afternoon.
Reiss-Alexander Russell-Denny's 36th-minute strike had given the hosts the initiative heading into the second half at Kingsmeadow stadium.
But Richard Beale's young team showed an abundance of resilience and character to change the course of proceedings. England youth international Whitwell levelled on 77 minutes, before striking again in stoppage time to send the Baggies' youngsters home with the points.
Senior forward Devante Cole kept up his match sharpness by playing 78 minutes of the triumph, while there was also a first start for recent 21s addition and New Zealand U19 international Joe Wallis between the sticks.
Chelsea dictated much of the play in the capital, and made the most of their possession when Russell-Denny converted from inside the box to make it 1-0 before the interval.
This meant Albion's PL2 team had to remain patient agains the Blues, utilising counter-attacks and second balls to hurt the hosts - which is exactly how they found an equaliser.
A swift turnover in play was executed to perfection, and eventually finished off by midfielder Whitwell - who kept up his good form in front of goal by notching in back-to-back league games.
At 1-1, Chelsea, as expected, asserted their grip on the game in an attempt to get themselves on the right side of the scoreline once again.
Instead, though, Beale's boys dealt a decisive blow - pouncing on a mistake by home goalkeeper Max Merrick to allow Whitwell a clean run on goal and the simple task of rolling the ball into an empty net to complete the comeback, and seal three impressive points in the PL2.
Even though he was delighted with his contributions, the Baggies' match-winner wouldn't be drawn on his personal performance - stating Saturday's win proves that Harry, and his team-mates, can compete "with any academy in the country".
Whitwell said: "Going down early in the game is never ideal, but the team showed really good character to stay in the game and not concede again.
"That then gave us the platform to stay in the game, build, and our fitness levels showed as we scored the goals in the final 20 minutes when it mattered most.
"It was a tough start to the season with two heavy losses. But we've bounced back in the last few games, it's been really positive, and we've showed we can compete with any academy in the country.
"To get a win against a side like Chelsea is a great feeling for everyone involved.
"They invest a lot into their academy, so to show we can compete with sides like that is a real positive and now we can look to kick on because we have confidence and know we can beat these big teams.
"There'll be other challenges ahead, but I'm sure we can deal with others that come our way this season."
Albion: Wallis, Nelson, Richards ©, Diomande, Shaw (Humphries 78), Deeming, Dauda Iddrisa (Parker 63), Whitwell, Heard (Sule 63), Higgins, Cole (Walker 78).
Subs not used: Wilkes (GK).
