Remember, Andre Blake has been in MLS his entire career, meaning he is at the level where you're good enough to have a solid MLS career, but not good enough to go abroad to a better league. I believe it was 2019(?) playoffs where Philly got knocked out in a game where Blake was horrendous.
He's good, but he's not invincible.
But let's beat Montreal first!
Edit: in 2019 Philly actually beat RBNJ 4-3 despite a very poor game from Blake.
He very recently conceded 4 goals to Charlotte.
OTOH he only conceded >1 goal just 3 times all season.
Another interesting item: the Union had fortunate scheduling in that they played Away both at Montreal and at NYCFC while those teams were in CCL, and Philly won both games. The Union edged out Clubfoot by just 2 points and Montreal had more wins. Convert either one of those 2 well-timed Away games to a draw and Montreal wins the East.
The Union's H/A adjusted opponents' PPG for the last 16 games of the season when the Union dominated was just 1.18. And they converted shots at a ridiculous rate over that stretch when their Goals exceeded xG by +14.2. They were -4.4 G-xG during the first 18 games. I don't think they suddenly got better at converting. Apart from chance and luck, I think they played a lot of crappy teams in the second half who gave up against the Shield contender/leader as soon as they fell behind. Credit to the Union for maintaining their energy while up 3-0, 4-0, and more, but it's a lot easier to score when the opponent has no reason to try and probably does not.
To be clear, their defense excelled all year, and their xGD for the year was better than both Montreal and NYC, and second only to LAFC. And the schedule strength for the Union, Clubfoot and NYC all year was effectively identical.
The Union are really and indisputably quite good. But not as good as their second half appears.
Nobody really noticed this, but Montreal achieved 15 of their 20 wins by 1 goal margins and were 15-6 in 1-goal games. For comparison, New England had 18 (out of 22) 1 goal victories last year. It's similarish, and we know how that went. The Union had just 6 1-goal wins out of 19 against 3 1-goal losses, and NYCFC won 7 and lost 8.
We're are properly deemed underdogs against Montreal, and will be again against the Union if we win Sunday. Especially Away for both. But both of those teams had some good fortune this year while NYCC had to deal with the coach and best player leaving midseason and a shit ton of injuries.