Titanic means something really big and strong. In football we use it to decribe a match - usualy a big match between two big/powerful teams - that has had lots of incidents. The game also has lots of meaning for the competition in which it was played - an important league match, a play-off, a semi-final for example - so a lot at stake. The example was from the game between Man City and Liverpool as they both were fighting for the title.

Emphatic in the second example means to hit the ball with real force (very hard indeed). An emphatic finish would be a goal scored with a hard shot. An emphatic win would be a very good win when one team has easily defeated the other team (maybe by a big score).