The Dragons had led 22-5 thanks to the boot of Tom Prydie and a try from Steffan Jones. Munster stormed back with tries from Ronan O’Mahony, CJ Stander and Johne Murphy to take the lead with eight minutes to go.
But Wardle crossed with minutes to spare following a barnstorming break from Toby Faletau.
The centre would have been captaining Cardiff University in the Varisty Match at the Millennium Stadium on Wednesday had it not been for his meteoric rise.
But he provided further proof of his potential with another impressive all-round performance.
Prydie knocked over a simple penalty to hand the Dragons the lead at Rodney Parade but it was quickly relinquished as the home defence was caught napping
Keatley hit a hanging cross-kick into the corner, which Tonderai Chavhanga failed to deal with and Paddy Butler pounced.
Prydie’s second penalty restored the lead and it was quickly stretched.
Steffan Jones hacked forward some loose ball and although it evaded jet-heeled Chavhanga, it fell to Ross Wardle, who offloaded to Lewis Robling.
Robling was held by the Munster scramble defence but released Jones to score under the sticks with another sublime offload.
The Dragons full-back landed a third penalty on the half-hour mark as Paddy Butler was sin-binned for a ruck offence and Jones banged over a drop-goal in stoppage time to make it 19-5 at the interval.
Prydie kept the scoreboard ticking but Munster launched a devastating comeback with a hat-trick of quick-fire tries.
The Dragons were staring at defeat but they finished the season at Rodney Parade in style.
 Faletau made a barnstorming break and released an offload. Play broke down but the damage was done and the ball was spread to Wardle, who broke Munster hearts.
And Prydie’s fifth penalty wrapped up a sixth league win of the season and gave Dan Lydiate a perfect farewell.
