Meanwhile, in a medium bowl, whisk together the water, tomato sauce, ketchup, brown sugar, apricot preserves, vinegar, cumin, mustard powder, paprika and garlic powder.
Once the brisket has been seared, add the tomato sauce mixture to the pressure cooker. Move the brisket pieces around to ensure the liquid is both under and over it.
Attach the cover of the pressure cooker and seal according to manufacturer directions. Bring up to pressure, then adjust the burner temperature to maintain medium-high pressure.
Cook for 11/2 hours.
Remove the pressure cooker from the heat and place in the sink under cool running water. Once the pressure cooker has cooled enough to open, remove the lid. Test the meat; it should be fork tender.
Carefully transfer the meat to a platter and use 2 forks to pull it apart into bite-size chunks.
Meanwhile, return the cooker to the heat and simmer, uncovered, until the liquid has reduced and thickened. Return the shredded brisket to the cooker and toss well. Serve with slider buns.