The Celtics have more star power than Toronto, are deeper and have the best coach in the Eastern Conference if not all of the NBA in Brad Stevens. 
OK, so then why is this series tied 2-2? 
A miracle 3-point play with one-half second left in Game 3 and Boston missing 35 of 42 3-point shots in Game 4 are the reasons. 
Toronto plays outstanding defense. But the Celtics missed 22 of 27 uncontested looks from beyond the arc in the last game. I expect the Celtics to make a much higher percentage and for stars Kemba Walker and Jaylen Brown to play much better in this Game 5. 
The Celtics are due to bring their "A" game. Even if that doesn't happen, though, I like the Celtics' depth as the series goes deeper and fatigue becomes more of a factor.