Rizwan's words came when Brydon Carse was saved by DRS call on LBW by Sajid Khan.
Pakistan won the Test by 152 runs and leveled the three-match series 1-1.
The incident happened when a review taken by England tailender Brydon Carse went against the home team on day four of the second Test.
After being declared lbw, Carse was persuaded by his partner and skipper Ben Stokes at the other end to seek a review. He was given out sweeping when Sajid Khan's quicker one hit him on the front leg, but the review system revealed that the ball's spin would have caused it to miss the leg stump.
Umpire Kumar Dharmasena was therefore instructed to alter his ruling.
"That's why I don't believe in DRS," Rizwan said before the next delivery was bowled.
Pakistan had batted first after winning the toss and posted 366 in the first innings with debutant Kamran Ghulam making 118 and Saim Ayub making 77 runs. In response, Ben Duckett’s 114 helped England make 291 runs. For Pakistan, Sajid Khan starred with 7/111, while Noman Ali took three wickets.
Salman Agha’s 63 helped Pakistan to 221 runs and set England 297 runs to win. However, England's batting collapsed to 144 and lost the Test by 152 runs. Noman Ali took 8/46 and completed 11 wickets in the Test.
The three-match series is now level at 1-1, with the final Test to be played on October 24 in Rawalpindi.