I would explain it by saying I have a very different opinion of Bellerin's strengths versus Tierney's. The only area I think Bellerin might have the edge is in his ability to time runs to get into good positions on the overlap, whilst Tierney tends to be more old school and hang closer to the touchline, backing his crossing from there. Although, I suspect this is less down to Tierney more to do with who plays in front of him.
The only thing I think Bellerin does well defensively is defend the back post because I think he reads crosses and tracks movement in the box well when the play's in front of him - although he can and does get outmuscled and outjumped a bit too often. Bellerin is, and in my opinion has always been, terrible one-v-one and his awareness is poor when players are running off him or in behind him out wide. Tierney, on the other hand, is a superb all-round defender, in my opinion. One-v-one he's as good as they come, and he's super switched on and aggressive in every other aspect of his defending. The only weakness I see is he still can get a little outmuscled and he's not great at reading the flight of the ball when balls come into the box. Unlike Bellerin, I expect him to get stronger and improve in the air.
