Victorino's seventh-inning grand slam ensured victory for the Red Sox, whose success in game six gave them an unassailable 4-2 lead in the best-of-seven American League Championship Series.
The match remained scoreless until the fifth inning, where Xander Bogaerts doubled with two outs before scoring a single.
But the Tigers took the lead immediately after and the momentum looked to be swinging their way until Victorino propelled them to a four-run seventh-inning and Detroit's hopes faded thereafter.
It is the third time in 10 seasons that Boston have sealed their spot in the World Series, but their first since 2007.
They will face the St Louis Cardinals, who saw off the challenge of the Los Angeles Dodgers 24 hours earlier.