Although United's in a really good form under Rangnick, City has been portrayed as a strong favorite today. I will join the bookies' opinion here in expecting City to win in the derby - they will know how to use all the gaps that United is leaving - United cannot win the midfield battle against City.
City have little or no choice but to win today, Liverpool are breathing down their neck as the title race heats up, a slip up would be a disaster in every sense of the word and Liverpool would capitalize, just as every City fan was watching Liverpool v West Ham yesterday praying for an upset, i am pretty sure the kops would have their popcorns ready for this game, Liverpool have a great rivalry with United, but all that will be put aside for 90 mins, as Liverpool fans would cheer United to victory today in their homes and from wherever they are watching, it is going to be a really intense contest.
The other game is important as well, if United loses and Arsenal manages to win Arsenal will surpass United and climb to 4th spot with 3 games in hand - meaning they would be huge favorites for the last CL spot.
Arsenal are favorites to beat watford and also favorites for 4th position in my opinion, i hope they can keep up their good form and pick up the needed points, they have been away from the CL for awhile now, and i am pretty sure their fans will be itching to get back into the competition.