Yes, Arizona and Gonzaga will defeat their opponents, because both of these programs have a long tradition. These programs know how to win. That legacy of how to compete in a clutch situation is passed down, and current competitors know how to keep their cool. Ultimately, experience will prevail and these teams will progress far into the tournament.
Entering the tournament Arizona is ending the season on a low note. They have not been playing there best basketball and this is the wrong time of the year to not play your best. On the other side, Gonzaga has been playing well and have lost a number of close games to tournament teams. These close calls give a team valuable experience and that is a key ingredient to tournament success.
Arizona has already lost to Wichita State. That makes it impossible for a win, as they are now done. Gonzaga has beat their first round opponent, but I don't think they have what it takes to beat Utah, which is their next game. As always, anything can happen in March, though.
Arizona is a highly overrated basketball team. It's seeding is not reflective of its actual performance during the course of the year. Conversely, Gonzaga is a much better team than it is given credit for. This team has an excellent opportunity and shot to advance to the Sweet 16, and perhaps even further.