Student or Learner
In all honesty, I did not expect Singapore to beat Vietnam(,) as Vietnam were far more superior in terms of teamwork, fitness, passing and movements.
1. Is a comma needed after "Vietnam"?
2. Is it correct to use "more superior"?
Thanks in advance.
Yes, it would be incorrect not to.
There is a pause there in speech, and the pause (and comma) are necessary to avoid the possibility of "Vietnam as Vietnam", which could make sense in some contexts.
"I expected Singapore to win in some of the provincial matches in Vietnam, but I did not expect Singapore to beat Vietnam as Vietnam."
Of course, that's not the most convincing example, but the use of a comma in such circumstances is to prevent the reader from having to read the sentence twice. A comma should be used if it's likely or possible that a phrase is going to lead a reader astray - though the likelihood in this case is low.