Splitting the two-game exhibition series in Germany, both nations are off to Athens on Monday for the Olympic Qualifying Tournament.
Barrett, 35, who saw 19 minutes of game action, also chipped in with two rebounds in the losing cause.
One-time NBA most valuable player Dirk Nowitzki, who plays for the Dallas Mavericks when not suiting up for his native Germany, netted a game-high 25 points.
In Athens, Canada opens with a game against Slovenia on Tuesday, followed by Korea on Wednesday.
Canada needs at least one win in those two games to secure a spot in the quarter-finals.
