Franz Wagner scored 22 points and eight rebounds for the winners, Dennis Schroeder scored 21 points, Andreas Obst scored 18 points, and Maodo Lo collected ten points and six assists.
For the Montenegrin national team, Nikola Vučević scored 23 points, ten rebounds and five assists, Kyle Olmen, who played for"VEF Rīga", scored 18 points, Igor Drobņaks scored 13 points, eight assists and six turnovers, and Marko Simonović had 11 points and six rebounds.
It has already been reported that in the first Group B game, the Lithuanians defeated Great Britain 94:70.
Later today in Tampere, host Finland will face Sweden.
In the first Group A match in Riga, Portugal defeated the Czech Republic 62:50. Latvia and Turkey are currently playing, but the Serbia and Estonia match will take place at the end of the day.
The first matches in two more subgroups in Poland and Cyprus will be played on Thursday.
The European Championship final tournament will feature 24 teams divided into four groups in late August and early September in Riga, Tampere, Katowice and Limassol. The top four teams from each group will qualify for the knockout tournament, which will be held only in Riga.