Cam Schlittler starting Game 3 wasn’t always a guarantee.

He wasn’t even on the Yankees’ roster to start the season, and he needed to earn the spot over both Luis Gil and Will Warren.

But Schlittler rewarded Aaron Boone’s call with the rookie by tossing eight scoreless innings in the Yankees’ 4-0 Game 3 win over the Red Sox in their AL wild-card series, while also striking out 12 batters — a postseason record for a Yankees rookie —in a dazzling postseason gem.

He allowed just five hits, walked zero batters and when Boone sent him back out for the eighth at 100 pitches, he only needed seven more to record his final three outs.