The Senators earned it — the game and the expected-goals battle both.
Ottawa dominated by shot quality. The Senators generated 4.54 expected goals to Montreal's 2.11, controlling 68% of the 5v5 battle. More striking: high-danger chances favored Ottawa 9–1, a gulf that renders the 5–2 final score understated.
Montreal kept the shot volume reasonably close—22 to 29—but quality diverged sharply. At 0.044 expected goals per shot, the Canadiens generated offense with less efficiency than Ottawa's 0.072. This explains why S. Montembeault, faced with 29 shots, gave up 5 goals. L. Ullmark, facing 22, allowed just 2.
Where Montreal struck. The Canadiens' power play was dangerous: 2 goals on 5 shots (0.42 xG). On the rush, they converted 2 of 23 chances—solid, though Ottawa's rush conversion (4 of 28) still outpaced it.
Where Ottawa separated. The Senators dominated the net-front battle, generating 4 rebound opportunities and converting 1. Brady Tkachuk's snap shot from the high slot at 12:43 of the third period opened the floodgates. J. Spence (2A) and T. Kleven (2A) ran the offense; both logged over 20 minutes.
The underlying margin was comprehensive. Ottawa's attack was sharper, their goaltender more composed under pressure, and their rush execution more lethal. Montreal's offensive sparks—especially the power play—came too sparsely to matter.