Having beaten Wycombe Wanderers 5-0 in their first pre-season fixture on Wednesday, Chelsea would have expected a similarly strong showing against Wimbledon at Kingsmeadow.
But Jose Mourinho's men were up against it as Alan Bennett scored inside the first minute and Matt Tubbs - who joined from Bournemouth last month - scored from the penalty spot shortly before the break.
Chelsea improved after the break, however, and three goals in the last 15 minutes saw them complete the comeback
Centre-back Terry - on as a half-time substitute - scored either side of Mohamed Salah's equaliser, while young midfielder Lewis Baker had a hand in all three goals.
The visitors handed a first appearance to Kurt Zouma. The centre-back joined from Saint-Etienne in January but remained on loan at the Ligue 1 side for the rest of last season.
Wimbledon made a flying start and Mark Schwarzer was picking the ball out of visitors' goal inside 40 seconds as Bennett leapt above Andreas Christensen to head home a corner at the back post.
Chelsea applied plenty of pressure in an attempt to get back into the game with midfielder Jeremie Boga looking particularly lively, but the away side were frustrated by Wimbledon's deep defensive line.
Things worsened for Chelsea five minutes before the break. Zouma was adjudged to have felled Tubbs in the area and the striker picked himself up to coolly dispatch the penalty to the right of Schwarzer.
The away side upped their game after the break and Marco van Ginkel wasted a great chance to pull a goal back when he headed straight at goalkeeper James O'Shea.
Chelsea did find a goal in the 74th minute, however, Terry poking home after a spell of pinball in the Wimbledon box from a Baker corner.
Parity was restored with seven minutes remaining when Salah drilled home a left-foot half-volley after collecting Baker's pass.
And the comeback was complete in the 89th minute. Wimbledon failed to deal with another Baker corner and Terry was on hand to head home the winner.
