It's a synonym of 'outplay', not the same thing...or they wouldn't be two words.
One means that something is in a separate classification to the other (ie, Spurs, in your example, are a class above us). Now that's a pretty unsubtle term to use for something that can change so quickly like a game of football between two equal teams...which is what happened and why 'outplayed' is the more apt term to use.
If you were talking about Barcelona versus Everton here and they put in the same first half performance as Spurs did, then you'd be within reason to say it was a gulf in class...because we know their standards are not going to slip...they could do that 9 times out of 10 to us or more.
outclass
aʊtˈklɑːs/
verb
past tense: outclassed; past participle: outclassed
1.
be far superior to.
"Villa totally outclassed us in the first half"
synonyms: surpass, be superior to, be better than, outshine, overshadow, eclipse, outdo, outplay, outmanoeuvre, outdistance, outstrip, outrun, outpace, out-think, get the better of, dwarf, put in the shade, upstage, transcend; More
That's pasted from the first page of Google and even has a reference to villa for some reason .
Your bold... They were.... "In the first Half"