Emile Poirier nearly put the Flames ahead just prior but, in a bid for his second goal of the night, he rung a shot off the post.
On the go-ahead goal, Joni Ortio stopped Jordan Eberle but couldn't control the rebound and it was whacked in by Marincin from in front with just under five minutes left in regulation.
Edmonton also got goals from Ryan Jones and newcomer David Perron.
Edmonton native Taylor Fedun had a pair of assists. Fedun, 25, played last year with Oklahoma City after missing the entire 2011-12 season with a broken femur. Fedun turned pro in 2011 after graduating from Princeton.
Calgary's other goal came off the stick of veteran Mike Cammalleri.
The match-up was one of two split squad games taking place between the two provincial rivals. They were also were playing at Rexall Place in Edmonton.
Both teams split their goaltending with Calgary veteran Joey MacDonald starting against Jason Labarbera.
MacDonald yielded Jones' goal on a tip-in 3:41 into the first period. It was the only goal he surrendered on 11 shots.
Labarbera, acquired in the summer to be Devan Dubnyk's backup, was perfect on 12 shots faced for the Oilers.
Calgary had the more veteran lineup but it was Edmonton that took a 2-0 lead to the third period.
The Flames finally got on the scoreboard when a big rebound from Richard Bachman was buried by Poirier, who was one of the Flames' three first-round picks in the June draft.
Selected 22nd overall, Poirier showed his quickness and nose for the net all night and was one of the best of the Flames rookies in the lineup.
Ortio, 22, who played in the Finnish Elite League the past two seasons and is one of five Flames goaltenders battling to replace Miikka Kiprusoff as the team's starter, played the second half for Calgary and yielded two goals on 10 shots.
Notes: Throughout the game, special recognition was paid to the thousands of contractors that helped get the Scotiabank Saddledome game ready after the June flood. Contractors involved in the repairs were given tickets to the game. ... Playing left wing with Sam Gagner and Eberle was Ryan Hamilton, 28, who has spent the past seven seasons in the AHL with the exception of 12 games he got into for the Maple Leafs. ... The only fight was between Calgary's Blair Jones and Edmonton's Travis Ewanyk. ... Edmonton was 1 for 3 on the power play while Calgary was 0 for 3.