Maas was an offensive co-ordinator for the Ottawa Redblacks last season. Edmonton brought the former quarterback on board as head coach after Chris Jones departed for the Saskatchewan Roughriders.
Anthony Barrett and Bryant Mitchell each had touchdown catches for the defending Grey Cup champions. Quarterback Jordan Lynch scored on a one-yard plunge for the Esks.
Sean Whyte kicked a 49-yard field goal for the defending Grey Cup champions, but missed from 49, 38 and 42 yards.
Stampeder defensive back Ciante Evans scored on 76-yard fumble return in the fourth quarter.
Rene Paredes made field goals from 23 and 14 yards in front of an announced 28,367 at McMahon Stadium.
Maas’s Calgary counterpart Dave Dickenson also made his head-coaching debut Saturday.
The new coaches played both starting quarterbacks briefly in the opening quarter before sending out all their backups.
Bo Levi Mitchell completed five of six passes for 56 yards on Calgary’s opening drive before taking a seat. Edmonton No. 1 Mike Reilly lasted two drives, going 5-for-8 for 54 yards.
James Franklin threw for 94 yards and a touchdown pass to Barrett in the first half before giving way to Lynch and Thomas DeMarco in the second.
Lynch led the Esks in rushing with 36 yards. He ran for a touchdown, threw a four-yard scoring pass to Bryant Mitchell and finished 5 for 9 in passing for 49 yards. DeMarco completed three of seven passes for 13 yards.
Calgary’s Drew Tate was 7 for 12 in passing for 67 yards before he was replaced by Canadian university star Andrew Buckley for the final three minutes of the quarter.
The two-time winner of the Hec Crighton Trophy that goes to the top player in university football finished the night 6 for 10 in passing for 74 yards. Bryant Moniz threw two interceptions on four passes in the second half.
Calgary receiver Joe West had 80 receiving yards by the end of the opening quarter.
But it was the defence producing the host team’s lone TD, however, when Evans ran the ball in off a DeMarco fumble at 4:22 of the final quarter.
Lynch dove on a third-and-one for a major at 7:17 of the third quarter, followed by a four-yard touchdown throw to Mitchell at 11:40.
Franklin found Barrett in the end zone with a 15-yard pass to score the game’s first touchdown at 9:12 of the second quarter.
The Esks started that scoring drive at Calgary’s 51-yard line thanks to Jimmy Gaines recovering a fumble by Calgary returner Tori Harrison.
The two clubs posting league-best 14-4 records in 2015 traded field goals on their opening drives. Whyte was good from 49 yards, while Paredes scored from 23 yards out.
But Whyte had his struggles as he was wide left on another attempt from 49 yards. He put a 38-yard try off the right upright and missed again right on a 42-yarder. Whyte also missed the convert on Edmonton’s first touchdown.
For the first time since Nov. 11, 2007, the Stampeders had someone other than John Hufnagel as their field general, although Hufnagel continues as Calgary’s GM.
The Stampeders conclude their pre-season on the road against the B.C. Lions next Friday and return to Vancouver to open the regular season June 25.
The Eskimos are at home to the Saskatchewan Roughriders next Saturday. Edmonton opens at home June 25 against the Redblacks in the traditional rematch of the previous year’s Grey Cup finalists.