Robins skipper Marlon Pack headed the 56th-minute winner, his sixth goal of the season, a minute after Plymouth substitute Juvhel Tsoumou had cancelled out Steve MacLean's deflected opener from a 23rd-minute free-kick.
Yates said: "Our spirit is really good, our confidence is high. I always said that whoever gets there, I don't think form comes into it.
"It's two games of football so if you are losing in the first you have not got to chase it or do anything stupid because it is 180 minutes of football not 90.
"We know how good Torquay are - they have some quality players, but so do we. It will make an entertaining game. We drew with them away and got beaten 1-0 at home so we have got to try and put that right.
"We will have a decent journey back home with the three points and the staff will make sure we do everything to get it right for Tuesday when we come back in."