The hosts were slightly the livelier side in a low-quality encounter and hit the woodwork early on through Mehmed Alispahic.
Guimaraes' Antonio Tomane almost snatched a win to keep their qualification hopes alive but the draw, coupled with Lyon's win over Real Betis, means the Portuguese side are three points adrift of second-placed Betis having lost both games between the sides.
Alispahic's 25-yard volley against the bar for Rijeka enlivened the opening stages, after the first 10 minutes produced only Leon Benko's mishit and, for Guimaraes, a Jean-Pierre Barrientos free-kick into the wall.
Zoran Kvrzic's header forced a save from Guimaraes goalkeeper Douglas in between two attacks for the visitors, which saw Andre Santos shoot over from long range and Barrientos volley wide from six yards.
Andre Santos scuffed a shot wide before Rijeka again took the initiative leading up to half-time, Dario Knezevic heading wide before Alispahic curled an effort just past the post from the edge of the penalty area.
Douglas fielded another Benko free-kick early in the second half before Andre Santos and Tomane both forced saves from Ivan Vargic.
Ivan Tomecak curled over and Benko stung Douglas' palms as Rijeka were kept at bay.
And Tomane and Andre could not hit the target at the other end as the game meandered towards stalemate.
Douglas blocked a shot from the lively Benko, Rijeka's likeliest source of a breakthrough, and Anas Sharbini shot wide.
Guimaraes almost nicked the three points in the 89th minute but Tomane was denied by a brilliant save from Vargic.
And when Kvrzic then failed to unduly test Douglas, the points were shared.