Late in the third quarter, Leonard drove past 76ers forward James Ennis III. Leonard dribbled to the left before gathering and attempting a layup with his right hand.
Embiid, who was camped in the paint, quickly adjusted his body and emphatically blocked Leonard's shot attempt off the glass.
Embiid's block led to an easy transition layup by Ben Simmons. The basket gave the 76ers an 81-63 lead with under three minutes left in the third frame.
The 76ers big man, who battled flu-like symptoms before Game 5, had a strong performance with 17 points, 12 rebounds, two blocks, one steal and an assist. Leonard had a game-high 29 points with 12 rebounds and five assists.
Philadelphia picked up a 112-101 win over the Raptors to force Game 7. The series shifts back to Toronto for the final game of the Eastern Conference semifinals Sunday night.