Despite kicking off with a 180, Long only managed an average of 75.33. It was enough to beat his Northern-Irish opponent, however, as 'The Clonoe Cyclone' ended up averaging 74.45.
Both players lacked consistency in the first set, but a 83-finish on the bull saw Mansell take it. A strong 127-finish from his Canadian opponent then levelled the match as both players continued to struggle.
Long had the better of the play as he took set three. The North-American then missed three match darts in set four, but after Mansell missed double seven to send the match into a deciding set, Long kept his cool and booked his place in round two.
Click here for more information about the PDC
World Darts Championship, including schedules and the prize fund breakdown.
William Hill World Darts Championship
Saturday December 15
Afternoon Session (1230)
Richard North (92.82) 3-2 (85.99) Robert Marijanovic (R1)
Mickey Mansell (74.45) 1-3 (75.33)
Jim Long (R1)
Josh Payne v Jeff Smith (R1)
Max Hopp v Danny Noppert (R2)
https://twitter.com/OfficialPDC/status/1073952841197248514