The 22-year old Estonian striker, on loan from Norwegian side Viking, came off the bench to net the only goal at Easter Road in the 83rd minute which delighted manager Stuart McCall.
"He likes to go in behind, he's a strong boy," McCall said. "We felt we needed a bit of freshness in the last 15-20 minutes.
"When you bring subs on you ask them to make an impact and thankfully that was the case. We asked him to get in the left channel because we thought there was space."