Raonic saved a match point when serving at 4-5 in the fifth but neither player gained another advantage until Raonic's break in the 57th game of the match. He then held serve to even the series.
The doubles match Saturday -- in which Canadians Daniel Nestor and Pospisil take on Ilija Bozoljac and Nenad Zimonjic -- will give one country the edge going into the reverse singles Sunday.
Djokovic meets Raonic, ranked 11th in the world, in the first match Sunday with Pospisil playing Tipsarevic in the potential deciding match.
The winning team moves into the Davis Cup finals in November against either the Czech Republic or Argentina. The Czechs, who won the Davis Cup in 2012, took a 2-0 led in that semifinal Friday.
Raonic finished with 34 aces and 29 service winners but his more aggressive style was also shown in his 83 unforced errors. Tipsarevic had nine total break points but seven of those were in the first and third sets.
Raonic won about three-quarters of the points on serve in the sets he won.
Djokovic claimed 82 percent of the points when he served Friday. He didn't allow Pospisil a break point and dropped a total of 10 points serving in the win.