Injuries has been curse this season, no doubt about that. Title contenders... Not so sure (but not worried as LVG's first season was always about steadying the ship and get into top 4)
Don't really think Smalling has had a good season. I get close to a heart attack, every time he think he's Beckenbauer, and starts to dribble up through the field. In defence of Smalling, the system played earlier in the season (3 at the back) didn't suit him nor Jones.
With regards to Mata, yes he is a fab player, but again the system Van Gall had utd playing doesn't suit his qualities. Mata is a great no. 10, in a tight 4-4-1-1 or 4-3-1-2 with one winger, but if you play two wingers and two strikers, the midfield gets thin defensively when he plays behind the striker/strikers. LVG want to play with two pacy wingers (the utd way), and pace is not his strength. I will not be surprised to see Mata leave in the summer (despite him having a good game today)... It could be a straight fight between Mata and Fellaini to be no. 10 in the 4-3-3 system played today, which LVG normally favours.