Munster picked up four important Heineken Champions Cup points in France when it looked like they were going home with just one.
Castres lead by four going into the final minutes of the game only for Gavin Coombes to outstretch a hand over the try line with two minutes to go.
It was the culmination of Tadhg Beirne forcing a turnover of the ball minutes earlier. Jack Crowley found the touchline with the resulting penalty and Munster enjoyed a rare lineout win.
The Munster contingent will be breathing a sigh of relief as it puts them top of Pool B, for now. Many of the pool teams have still a game to play this weekend.
The lineout will be a big talking point going into next week's group clash with Wasps. That along with some of the decision making and ball carrying.
Only minutes before Coombes gave Munster a lifeline - Peter O'Mahony decided against taking three points and opted for a kick into touch after John Hodnett's fine run earned a penalty.
People were left hoping it was a decision O'Mahony and co wouldn't regret, but a minute later Castres went and stole the resulting lineout.
The gutsy nature of O'Mahony is never questioned, as he enjoyed a fine first-half, but without Coombes saving the day it would have been a major talking point.
The lineout struggled and Munster made mistakes when they were out in the open. Crowley's handling error near the Castres try line at a pivotal moment in the second half was an example of such.
Jack Crowley Impresses
It's not a game Munster or Castres fans will want to watch back anytime soon but there is plenty of room for optimism in other areas - including the performance of Jack Crowley.
A lot of pressure lay on the 22-year-olds shoulders in the absence of Joey Carbery and Ben Healy. Last weekend only marked his second start for Munster.
Despite a handling error as mentioned above, he couldn't be faulted for his kicking. His three penalties and conversion made all the difference in the end.
It's another promising performance from a young Munster contingent that seems to be building around the squad. Crowley has come through after representing Ireland at U20 level.
Johann van Graan will go back to the drawing board to sure up the mistakes made on Friday night. A win away to Castres regardless of the performance is still a big hurdle to overcome.