Like others said, Anderson hurt DC pretty bad with a body kick despite it being his only real attack of the fight.
I think in the Stipe fight it was a couple of factors combined that lead to the finish. DC was clearly tiring from round 3 onwards, his was keeping his hands super high and extended to oaw at Stipe's hands and then landing strikes off the same pawing movements. Leaving his body completely exposed. The body shots hurt him and lead to the finish but it was ultimately a right to the chin that started the end. DC's hands dropped from the sustained body attack, and Stipe went high and rocked him. Like Conor being rocked by Nate, it seemed like it was more fatigue than it being a super hard shot.