Conor Chaplin's second-half header and a late breakaway from Luke Thomas ensured Championship strugglers Barnsley progressed to the fourth round for the first time in seven years with a 3-1 win at Crewe.
Chaplin's deft work set up Brown for a neatly-struck volley which flew into the far corner beyond keeper Will Jaaskelainen for the opener. Barnsley could have added to their lead during an impressive opening in which Jaaskelainen tipped around a fierce blast from Alex Mowatt and the Crewe keeper held onto a first-time effort from Chaplin.
Dave Artell's side carved out two glorious first-half openings only for in-form marksman Daniel Powell to miss both. Perry Ng slid the attacker clear, but Powell drove into the side netting. Then he should have made the most of Tommy Lowery's ball arrowed out of reach of keeper Brad Collins across the face of goal, but steered wide of an empty net.
Crewe rallied well, though, and were worthy of their equaliser soon after the restart (48) when Charlie Kirk sent the ball back over the six-yard box for Green to apply a close-range header.
But the gulf of two divisions eventually told and with Chaplin playing a key role the Tykes offered the greater threat in the closing stages. Brown lashed over after Jaaskelainen's punch failed to clear the box and the Crewe keeper managed to glove Clark Oduor's curling free kick onto the bar.
Chaplin restored Barnsley's lead (75) with a poacher's finish, stooping to head into the corner after Bambo Diaby headed Mowatt's free kick back across goal.
Then with Jaaskelainen up in the visiting box for a free kick in stoppage time Kenny Dougall released Thomas, who ran clear to finish into an empty net in stoppage time (90+4).