Namibia had other ideas and put their opponents to the fire early as Sri Lanka limped to 21-3 after 21 deliveries.
The wickets continued to tumble as the Asian Cup champs couldn't handle the constant pressure being applied by the bowlers.
Sri Lanka looked back on the right track thanks to a 34-run partnership between Bhanuka Rajapaksa and Dasun Shanaka. The departure of Rajapaksa however saw Sri Lanka lose four wickets for only 18 runs, eventually being dismissed for a lowly 108.
Frylinck, after his contributions with the bat, produced a stellar display with the ball in hand, finishing with 2-26 from his four overs as he claimed man of the match.
"What we just achieved is above what we thought we could do," he said after the historic win.
Bernard Scholtz, Ben Shikongo and David Wiese all secured two wickets for Namibia who barely put a foot wrong following their early batting collapse.
Cricket fans were floored by the staggering upset to get the tournament off and running.
The nightmare first-round result spells further doom for Sri Lanka who not only lost the contest but were wiped off the park by Namibia.
A one-sided defeat puts them well behind in net run rate side and they'll be hoping results go their way in the remaining group games so they can avoid a tougher draw in the Super 12.
Sri Lanka will look to bounce back when they take on the UAE on Tuesday while Namibia will square off against the Netherlands earlier on the same day.