I think Aston Villa may have a better chance, Ajax hasn't done so well in recent years and I think Aston Villa has been on the up lately as well. This is a knock off stage game so we would never know ,anything could happen so we should be ready for any result. I wagered on Villa to win but I had no confidence in that bet at all to be fair.
On the other hand, Aston Villa is in its best overall performance, Unai Emery fleet is even able to stay in the top four of the EPL standings to date. In terms of squad strength and depth, it is clear that Aston Villa currently deserves to be the favorite when facing Ajax, and betting on Aston Villa winning is quite safe.
Personally, I see Aston Villa as one of the teams that has the potential to reach the final round, other teams that have a chance in my opinion are Fiorentina and Fenerbahce. However, let's see how the last 16 of the Confederacy League will go run, the teams in this competition are difficult to predict. Not a few teams are able to display a different performance than in their Domestic League.