In the 2018 battle in Avengers: Infinity War where Thanos acquires the Time Stone, we have Thanos vs. Iron Man, Doctor Strange, Star-Lord, Nebula, Spider-Man and Mantis. We are led to believe that the only reason they are unable to beat Thanos is because Quill loses his cool and because Thanos is wielding all but one of the Infinity Stones.
In the 2018 battle with Thanos three weeks after the events of Infinity War, on his "retirement planet" (the Garden), we have an arguably superior force of Iron Man, Thor, Captain America, Captain Marvel, Hulk, and Rhodes all in peak form against an unarmed and unarmored Thanos (with zero stones) who is weakened and injured already -- not to mention that he no longer has any motivation to live. But he holds his own for a surprisingly long time. (Until he is eventually beheaded.)
Why is Thanos able to hold his own? Does it have to do with whatever his natural characteristics/powers are and/or are there other plotpoints at work?
... besides the needs of the movie to offer some excitement here, of course.