Fridolina Rolfo fired home from the penalty spot with 15 minutes to play to complete the defending champions' fightback and seal a 2-1 aggregate victory, after Emma Hayes' side had been made to endure the final half-hour on Saturday with 10 players following the sending-off of Kadeisha Buchanan.
Barca had already levelled the tie via a fine finish from Ballon d'Or winner Aitana Bonmati by the time the Chelsea defender saw red.
Reaching for a loose ball inside the centre circle, she landed a foot on the ankle of Patri Guijarro and referee Iuliana Demetrescu did not hesitate in showing a second yellow card.
It was a sad night for Chelsea manager Emma Hayes, who's leaving at the end of the season. (AP PHOTO)
In Hayes' final season in charge at Stamford Bridge, Chelsea battled gamely to give their outgoing manager the chance to depart on a high in next month's final in Bilbao, but they sorely missed the cutting edge of their injured Australian superstar striker Sam Kerr.
Despite Barca being camped in their own half, time ran out on the home side who bowed out in the last-four for the second season running.
The first 20 minutes passed almost entirely without incident before Hannah Hampton was finally forced into a save, dropping low to gather Caroline Graham Hansen's tame right-foot volley from the edge of the box.
The game needed a moment of skill and fortune to crack it open, and on 25 minutes it got both.
The ball was played into the feet of Bonmati, who with a clever step-over outfoxed Niamh Charles before hitting a shot that deflected against the outstretched leg of Buchanan and beyond Hampton's reach to level the aggregate score.
Chelsea almost hit back immediately. Catarina Macario slipped a ball through the left channel to Lauren James, who cut the ball back from the byline for the unmarked Melanie Leupolz. Six yards out and with the goal at her mercy, she sent a left-foot effort crashing against the crossbar.
Sjoeke Nusken's shot on the slide spun agonisingly against the outside of the post as Chelsea came close to going ahead but after Buchanan's dismissal came the penalty award, with Jess Carter putting an arm in the back of Bonmati who then tumbled over Lawrence.
VAR checked and saw nothing wrong with the decision, and up stepped Rolfo to send Hampton the wrong way and ensure Hayes leaves to take over the USA job without the European trophy she had coveted for so long.
