Is this person better than you (in the field you're talking about)? Probably not. If he was, he wouldn't be concerned with even looking at a lesser (such as you), much less talking about you.
Maybe this person feels he's on his way to being better than you. Let's say he gets there: the work necessary to get there will make him appreciate the effort involved. There won't be much talk then, since to get to that level, he will be dealing with enough people talking about him that he won't have mental space to focus on others.
Odds are he won't get there though: people work harder when they're somewhat unsatisfied with where they are. Those who talk shit online derive great satisfaction from it -- that's why they do it! That satisfaction actually deters action. Pulling you down (or at least thinking he is) makes him feel that you and him are closer than you are in reality. That gap doesn't really exist, he thinks. Thus, no need to work, and no achievement.
When was the last time someone who was clearly better than you talked shit to you unsolicited (i.e., they started the conversation)? You'd be hard pressed to even recall this happening. Keep that in mind when the rubber bullets of the Internet are pointed at you.
#WorkOnYourGame