Substitute Yousef Salech equalised with three seconds of stoppage time remaining as Cardiff snatched a 2-2 draw at Millwall.
The Bluebirds were trailing to early goals from Calum Scanlon and Casper De Norre before Chris Willock pulled one back before half-time.
Millwall looked set to cling on for only their second win in 13 matches, but Salech – signed from Swedish side Sirius last week – denied them at the death as Cardiff rescued a point.
Liverpool teenager Scanlon had earlier scored his first senior goal to put Millwall in the lead after only 61 seconds.
The 19-year-old, who joined the Lions on loan in August but suffered a stress fracture in his back on his debut which sidelined him for five months, was clearly desperate to make up for lost time.
These sides had contrasting fortunes at the weekend, with Cardiff winning a memorable south Wales derby 3-0 against Swansea while Millwall were booed off after a home defeat by Hull which stretched their winless run to five matches.
So the start to the match came as a surprise to everyone at The Den.
Scanlon, a left-back by trade at Liverpool but pushed further forward by Lions boss Alex Neil, controlled Duncan Watmore’s pass out to the left flank.
He held off City defender Andy Rinomhota, strode into the penalty area and lashed his finish into the roof of the net.
Cardiff tried to hit back immediately but Callum Robinson’s low shot was easily dealt with by Lukas Jensen.
Instead Millwall doubled their lead in the 19th minute thanks to a superb piece of skill from another youngster, academy graduate Ra’ees Bangura-Williams.
The 20-year-old, making his full Championship debut, bamboozled Manolis Siopis with his footwork on the byline before cutting the ball back for De Norre to slot inside the near post.
Cardiff hit back on the stroke of half-time when Willock took aim from 25 yards and hit a fine curler into the top corner.
After the break Jensen held a long-range effort from Robinson and Willock fizzed a shot across goal and wide.
Millwall’s evening was soured when Danny McNamara, only just on as a substitute for the injured Ryan Leonard, twisted his knee horribly and had to be carried off on a stretcher.
The hosts could have had a third when Watmore met Tristan Crama’s cross with an acrobatic volley but it flew straight at City keeper Jak Alnwick.
But Cardiff pushed for an equaliser and Salech went close with a header before getting on the end of one last ball into the Millwall box and prodding home a last-gasp leveller.
