Cheltenham Town narrowly missed out on perhaps the biggest FA Cup upset ever, as Manchester City scored three times in the final 10 minutes to come from behind and win 3-1.
The Sky Bet League Two side went ahead just before the hour through Alfie May's close-range finish after a Ben Tozer long throw caused mayhem in the City box.
And just as the Robins could start dreaming of completing one of the most seismic shocks in the competition's 150-year history, a string of substitutions changed the game in the Premier League giants' favour.
Phil Foden fired in an 81st-minute equaliser and Gabriel Jesus quickly followed that up to put City ahead.
Ferran Torres' injury-time goal meant the scoreline ultimately did not reflect just how close Pep Guardiola's team came to a hugely embarrassing result.
City now go to Swansea in the fifth round.
But up until Ruben Dias and Ilkay Gundogan's arrival in the 68th minute, the City manager's decision to field a combination of youth players, second string and first-team regulars looked to have backfired.
Foden, Jesus and Fernandinho were all handed starts, and so too Aymeric Laporte, Benjamin Mendy and Riyad Mahrez.
However, goalkeeper Zack Steffen and teenagers Tommy Doyle and Taylor Harwood-Bellis were also included in an XI that lacked any kind of fluency.
The quest for Guardiola-esque free-flowing attacking football certainly was not aided by a bobbly pitch at Whaddon Road, and a lengthy first-half delay after fireworks were set off behind one of the stands.
Neither good enough reasons for City to struggle to the extent that they did against a team four divisions below.
And the Robins stunned their big-spending visitors in the 59th minute, only moments after Jesus had hit the post with a glorious chance.
Tozer’s long throw had been a threat all game, and after some pinball in the area an unmarked May ran through the crowd to stab home from inside the six-yard box.
City were struggling for answers, even after their changes, but having always looked most likely, Foden found one. With nine minutes left, he volleyed in a perfect cross from impressive substitute Joao Cancelo.
Jesus then completed the turnaround, firing in Fernandinho’s through-ball, before Torres scored with the game's final kick.