Both of the teams didn't lose their important players, so I predict Manchester United will win.
Although they were lose against FC Twente, but we should judge their performance in Premier League.
It is normal to see many people underestimate Man United because it is a fact that their performance is not good so far in EPL (both teams have the same result with 2W 1D 2L) but Spurs is better in scoring goals compared to United.
The odds for United shows that they are not that favorite in the game, it will be a tough and balanced game IMO and maybe the game will end in a draw.
If you are going to bet, it is better to avoid 1x2 market because it is hard game to predict due to the incosistency of both teams since the season started.
But if you are so sure that Man United will win, the odds is quite tempting to skip so you can bet on them as long as you are ready for the worse case.