The Perth men made the short journey east to Dens Park for the summer warm-up clash just three days after stunning Rosenborg in their second qualifying round first-leg tie with Frazer Wright's first-half winner.
There were further positive signs when striker Stevie May put the McDiarmid men ahead early in the first half, but Dundee claimed the draw with Carlo Monti's second-half strike.
European hero Wright was given the day off for the meeting with John Brown's team, although Tam Scobbie, Dave Mackay, Paddy Cregg and David Wotherspoon were all in the starting line-up after seeing duty in Trondheim.
Former Rangers, Dunfermline and Aberdeen midfielder Barry Nicholson, meanwhile, was one of two trialists named on the Saints bench by boss Tommy Wright.
The visitors struck early as May put them ahead. The forward latched on to Liam Caddis' through ball and was clinical with his low finish past Kyle Letheran in the Dee goal.
Substitute Monti restored parity after the break but Saints saw a late chance to claim the win wasted when Letheran denied May a second from the penalty spot.