The Saints were heading towards a first FA Cup final since 2003 when Finn Azaz's brilliant finish put the Championship side in front 11 minutes from time.

However, City avoided the same fate that Arsenal suffered in the quarter-finals and remain on course for a domestic treble.

Jeremy Doku's deflected effort quickly levelled before Gonzalez rifled in from long range three minutes from time.

City will face Leeds or Chelsea in the final on May 16.

"No team has made four finals in a row. It's extraordinary and hopefully we can arrive with a good momentum," said Guardiola.

Defeat ends Southampton's 20-game unbeaten run that has propelled them into contention for an immediate return to the Premier League.

The Saints also knocked out City's title rivals Arsenal in the previous round and will rue a glorious chance missed to return to Wembley next month.

Guardiola made eight changes from the side that went top of the Premier League with a 1-0 victory over Burnley on Wednesday.

Erling Haaland, Bernardo Silva and Doku were among those to miss out and City took 45 minutes to find their feet.

Leo Scienza found the bottom corner early on, but Southampton's joy was cut short by the offside flag.

City came out for the second half a changed team even before Guardiola turned to his bench to unleash the stars he had kept in reserve.

Omar Marmoush missed his chance to shine on a rare start ahead of Haaland.

The Egyptian spooned the best of City's chances over the bar before he was replaced by Haaland.

Guardiola also introduced Doku, Savinho and Nico O'Reilly to break down Southampton's mass ranks of well-marshalled defence.

Daniel Peretz repelled Gonzalez's powerful effort before Southampton pounced to take a shock lead on a rare second-half foray forward.

Kuryu Matsuki fed Azaz, who spun before unleashing an unstoppable effort into the top corner.

However, Southampton could not hold on as City roared back to reach the final once more.

Doku's effort from the edge of the box deflected off James Bree to wrong-foot Peretz.

The Southampton goalkeeper was then left helpless as Gonzalez's piledriver completed the comeback.

Savinho should have added a third in stoppage time after Peretz came forward in search of an equaliser and left his goal gaping, but Matsuki raced back to clear off the line.

City, though, did just enough to remain on course to match their own achievement of being the only English side to win the Premier League, FA Cup and League Cup, in 2018/19.