I bet on Sterling in their first match (luckiest bet I ever won) because I thought he would be able to take Yan down and work him on the ground. When Yan shrugged off the td attempts and then started out-grappling Sterling, it was a real holy shit, this guy is incredible moment.
No fighter is flawless, but Yan damn sure looks it right now. Dude has elite levels of striking, power, grappling, chin/toughness, and cardio. Only complaint I can think of is that is footwork could be a little more dynamic, but since he seems capable of marching anyone down, that might not be necessary. Even with the division as stacked as it is, it's hard to see anyone beating him.