By rule you cannot let the ground assist a catch and you must retain possession thru the ground even after exiting field of play. Both were accomplished. If WR has lost possession after going to ground then it would have clearly been ruled incomplete by rule. The fact that the WR retained possesion thru the catch then after hitting the ground retained the ball it was clearly a catch. It was a TD and anyone and I mean anyone that has been watching how these are called "correctly" over the season has a bias if they convince themselves it was questionable for more than a few angles. They wanted things to fall Pats way or they are griping over a bad call they have yet to get over that had no application to the Superbowl.
CATCH AND TD CHECK CHECK!
Los Angeles Rams
Rap on.