Batman regularly beats much-stronger opponents. That shouldn't be an issue. Strength only matters if you actually manage to punch or grab Batman. And you're not gonna manage to punch or grab Batman.

Spock only has one decent fighting move, and it targets the back of the neck. Batman's neck is so heavily armoured that he can't even turn his head.

Batman's ability to defeat stronger opponents is predicated upon his superior logical faculties, as we've already established. He's the Sherlock Holmes of Kickin' Ass. That said, he cannot hope to outmatch Spock in that regard, and, even should hand-to-hand combat be a factor, he would still lose on account of the Vulcan's clear advantages in strength and reflex.

No, Sherlock Holmes is the Sherlock Holmes of kicking arse, as demonstrated in the recent movie. Holmes' superior deductive abilities enable him to quickly detect an enemy's weaknesses and capitalise upon them; this serves him well against common street thugs.

When milliseconds matter, though, training and experience beat logic. And Batman has years of martial arts training followed by quite a few more years of practical ass-kicking experience in the streets of Gotham. This is why Batman could whup Sherlock Holmes and Mr Spock. (Sequentially, at least. Put them together and they'd outwit him with some brilliant plan.)