yeah, but does that mean it's actually a difficult fight or that just the general public perceived it as a difficult fight? because those are 2 very different things. Merab didn't look like he had a difficult time beating Umar no matter how close the fight was because Merab was literally showboating for a good amount of the fight, DDP also didn't look like he had difficulty beating Whittaker, evidenced by him destroying him in the 2nd rd. for example, Merab's fight vs Ricky Simon was much more difficult for him than Umar.
the same way many people thought Pereira would walk through Khalil and it would be an easy fight. in reality, it was a difficult fight for Pereira. but we don't still pretend it was an easy fight for him. so why are we pretending Merab and DDP had difficulties beating the guys people thought were hard fights for them? Merab had a close but rather decisive fight, and DDP blew Whittaker away.