Odsonne Edouard's 96th-minute winner ensured Celtic moved 10 points clear at the top of the Scottish Premiership courtesy of a 1-0 win at Dundee.
Scott Sinclair and James Forest both missed good first-half chances for the visitors while Scott Bain made a smart save to deny Scott Wright during a rare Dundee counter-attack.
It looked as though the hosts had done enough to earn a point, but another title is now looming for Celtic with Edouard meeting Forrest's cross to fire beyond Seny Dieng with virtually the last kick of the game.
Dundee: Dieng (7), Ralph (6), R. McGowan (7) Kusunga (7), Horsfield (6), O'Dea (7), Woods (6), O'Sullivan (7), Wright (7), Robson (6) , Miller (6).
Subs: Dales (n/a), C. Curran (6), J. Curran (6).
Celtic: Bain (6), Toljan (6), Lustig (6), Ajer (6), Tierney (7), Brown (7), McGregor (6), Forrest (7), Johnston (6), Sinclair (6), Edouard (7).
Subs: Benkovic (6), Hayes (7), Weah (6).
Man of the match: James Forrest.
Dundee manager Jim McIntyre may question the six minutes of stoppage time that was added on at Dens Park, at the end of a valiant effort from his side, who remain deep in relegation trouble just a point above bottom side St Mirren in 11th place.
It means Celtic earned another three points in their quest for an eighth league title, and it was a third time in successive away games that the champions snatched a stoppage-time winner meaning the travelling supporters celebrated St Patrick's day in style.
Having won 5-0 at this ground in November, another away win seemed a formality, especially in the opening 30 minutes with Celtic dominating possession. After 17 minutes, Sinclair forced Dieng into his first meaningful stop as he instinctively kept the forward's shot out from close range after good work from Callum McGregor.
Dundee made two changes to the side that lost to Hearts, changing to a back five. Dales and Curran dropped out of the side while O'Sullivan came in for his first start and Kusunga started in defence.
McGregor returned to the Celtic side with Lennon making four changes to the side that were held to a goalless draw against Aberdeen. Lustig and Toljan started in defence as Boyata dropped out of the squad. Johnston and Edouard came in for Henderson and Burke.
The chances continued to flow early on for the visitors as the Dundee stopper then produced a fine double save to deny Scott Brown from distance, and Sinclair on the follow-up. Dieng showed his defiance once more as he sprung to his left to claw out another shot from the Celtic winger with five minutes of the half remaining.
Dundee had done well to withstand heavy pressure, and were very nearly rewarded on the counter-attack as after Ethan Robson had released Wright through on goal, Bain had to be quick to close down the angle and save with his legs.
The second period was short on goal-mouth incident but high on delays with both Darren O'Dea and John O'Sullivan requiring treatment before Kristoffer Ajer was forced off with a facial injury for Celtic.
It seemed Dundee would secure an invaluable point, however, after seeing Forrest's shot from Brown's pull-back whistle past the post via a deflection off O'Dea.
But Edouard would have the final say, following his pass down the left flank to Forrest, escaping the outstretched leg of Martin Woods to prod home from close range and spark wild celebrations from Lennon down the touchline.
Man of the match - James Forrest
Edouard's late intervention means that Celtic have scored winning goals in the 89th minute or later in each of their last four away league games.
They fought until the very end again, but it was the energy of Forrest down the left, along with a lively cameo from Jonny Hayes, that got them over the line.
Forrest might have had an assist earlier in the game as Sinclair was denied by Dieng, but his industry would ultimately be rewarded.
He told Sky Sports: "It was massive at the end getting such a late goal. I think we didn't play our best today but the lads deserve plenty of credit. We just kept going for it and we got the winner right at the end.
"We know it's hard coming to Dundee as they're fighting for their lives but we wanted the three points as well. We're all buzzing."
Jim McIntyre: "We're devastated with the outcome of the result, obviously. I thought we put so much into the match and our defensive organisation was really good. We knew it was going to be a tough match, as Celtic are a top team, but we coped with a lot of it.
"The frustration for me is that we had chances to break in the six minutes that were added on, and we've got to be better.
"The boys that I brought on, they need to do better than that as that was an opportunity for us to get the goal, but Celtic showed their ruthlessness."
Neil Lennon: "It's a brilliant and a significant win. It's what we deserved over the course of the game. Dundee are fighting for their lives, so they were never going to just roll over.
"We could easily have been undone at the end of the first half but we produced that little bit of urgency and quality at the vital moment and Odsonne has repaid another huge chunk of his transfer fee with that goal today.
"We've got a two-week break now and some of them need it as they're dead on their feet. We won't take the 10-gap for granted, but it's a very welcome cushion at the moment."
Dundee travel to face St Mirren after the international break on March 30 while Celtic host Rangers in the Scottish Premiership a day later, live on Sky Sports.