With the scores 2-2 at full-time and finely poised at 3-3 in the shootout, Krysiak dived full stretch to his right to palm away Byron Anthony's spot-kick before Richard Duffy held his nerve to net the winning penalty for the Grecians.
Manager Paul Tisdale was suffering from flu and missed his post-match press conference, but Edwards said: "It was a fantastic save by Artur.
"Both sides took some great penalties and the difference was just one outstanding piece of goalkeeping. It was so important for us to bounce back from our derby defeat at Plymouth so we are delighted to be through.
"We practice penalties a lot and I was told by the lads they had netted 19 out of 19 in training so we were pretty confident.
"The manager wasn't happy with our first-half display and there were some home truths delivered at half-time. But it all came right for us in the end and hopefully we can now go all the way to Wembley."
Source: PA
Source: PA