Kendall came off the bench with only nine minutes left in normal time, then struck in the second minute of stoppage time to the delight of the travelling Daggers.
Tom Eastman produced a superb tackle to prevent the home side from opening the scoring on 17 minutes.
But Daggers then went close when Harry Phipps headed just over from a corner at the other end.
Freddie Sears got in behind the home defence to force a smart save from former Daggers keeper Mark Cousins.
Inih Effiong tried his luck from 30 yards on 36 minutes, but it was comfortably dealt with by Cousins, before Jake Hessenthaler was shown a yellow card.
Frank Vincent had his name take as well before the interval, as the scoreline remained blank.
But Daggers went close just three minutes after the restart with a fine move, which saw Josh Hare pick out Sears who fired wide.
And Lewis Page was denied what looked a certain goal by a save from Cousins midway through the second half, to the frustration of more than 250 travelling Daggers fans.
Rees received the third yellow card of the game for the visitors on 70 minutes, before Elloitt Johnson produce a vital block to deny the home side the opener.
Vincent made way for David Longe-King in the first change of the day for Daggers, with Sears subsequently replaced by Kendall.
Longe-King was the next Dagger to be denied by Cousins on 85 minutes, then picked up a yellow card moments later.
But Daggers were celebrating at the death as Kendall struck for three hugely important points.
Dagenham & Redbridge: Justham, Hare, Eastman, Phipps, Johnson, Page, Vincent (Longe-King 73), Hessenthaler, Rees, Effiong, Sears (Kendall 81). Unused subs: Weston, Francis-Clarke, Ling.