The second-ranked RedStorm, who were playing their MSC opener, improved to 5-1 overall with a fifth straight win.
The Bulldogs, who were also playing their league opener, slipped to 1-3 overall.
Maccauro broke a scoreless deadlock by scoring on a free kick with 13 seconds left in the first half. The senior forward from Sao Paulo, Brazil, curved a shot from 25 yards out around the Cumberland defensive wall and past net-minder Sully Shattuck.
Isberner, also a senior forward from Sao Paulo, Brazil, sealed the win with a goal at the 87:14 mark after he took a pass from senior midfielder Oliver Hewitt-Fisher (Swansea, Wales) down the center of the field and beat Shattuck near the top of the box.
Rio Grande enjoyed a 20-7 edge in shots, including a first half try which ricocheted off the crossbar and another which hit the post in the second half.
Senior goal keeper Jack Marchant (Leeds, England) was credited with two saves, including a stop on a breakaway by Cumberland's Harry Mason in the 28th minute.
Shattuck finished with seven saves in a losing cause for the Bulldogs.
The RedStorm returns to action on Wednesday night, hosting the University of the Cumberlands in an MSC game at Evan E. Davis Field.
Kickoff is scheduled for 7 p.m., following the women's contest at 5 p.m.