One of Grissom's primary inside players, 6-4 Jaquez Johnson, was unable to play more than a minute because of an injured shoulder.
McLelland turned in 15 points and four rebounds, while Jones added 11 points and a team-high eight rebounds.
"We thought it would be a battle of guard play, and that's exactly what it was," Grissom coach Bo Coln said. "The guards carried us here."
Grissom built an 18-9 lead through one quarter and never trailed. The Tigers will face defending 6A state champion Mountain Brook in Friday's finals at 9 a.m.
Woodlawn (21-12) was paced by De'Marco Herrod's 10 points. Javien Williams added eight.