Dumerc, who moved to UMMC from Bourges during the summer, was the club's biggest signing but missed the first six EuroLeague games through injury.
She is a pivotal player for a UMMC side that is looking to end Spartak Moscow Region's run of three straight titles in the competition.
UMMC never trailed in Wednesday's game though they did not begin to take command until late in the first quarter after Ilisaine David's jump shot had trimmed the home side's advantage to 9-7.
Starting with a Maria Stepanova free-throw, the Russian team went on a 16-2 run bridging the first and second quarters to lead 25-9.
In that spurt, Dumerc scored five points for the Russian team.
By half-time, UMMC were on top 39-21 and they lowered the boom in the third quarter, outscoring the visitors 26-7 for a 65-28 lead.
Gundars Vetra's side cruised the rest of the way as it improved to 6-1 in Group A.
Cras saw their four-game winning streak come to an end and are now 4-3.
Dumerc's fellow France international Sandrine Gruda had 16 points to lead all scorers with Stepanova contributing 11.
Agnieszka Bibrzycka and Ann Wauters poured in 10 points apiece for UMMC.
The Italians, who were out-rebounded 46-32, got 12 points from David.
UMMC were 24 of 50 (48%) inside the arc compared to Taranto's 13 of 44 (29.5%).
Angela Gianolla, Cras Basket Taranto:
"I have nothing to say, because the statistics speak for themselves. UMMC is the best team..."
Gundars Vetra, UMMC coach:
"It is the first game in a long period of time, that our team has played with its full roster. Our team has proved to be stable in every position. I'm happy that everybody is okay, and can play to their full strength. Comparing the two games [against Taranto] we can safely say that Taranto played better at home."
Sandrine Gruda, UMMC Ekaterinburg:
"It was really a very good game for us, we felt like a united team, taking a lot of rebounds and helping each other. We prepared for the match thoroughly, having analyzed our first game against our opponents."