Despite having an opportunity to run out the injured batsman, Udana waited for Marias to recover and return to the crease, denying the Rocks a potential wicket.
Considering the match situation, the 31-year-old paceman had every right to attempt a run out, but instead opted to abide by the "spirit of cricket" instead.
Marias recovered from the blow to crunch a six later in the innings, but it wasn't enough, as the Rocks secured a 12-run victory.
All-rounder Udana has played 15 ODI and 27 T20I matches for Sri Lanka since his international debut in 2009, claiming 35 international wickets. He featured in Sri Lanka's nine-wicket loss to Australia at the Gabba in October.
The Paarl Rocks sit in top spot of the Mzansi Super League ladder and have qualified for the final, which takes place on Tuesday, December 16.