Even if it was more than 20 minutes it's still not a feat, top tiers like Kaido, WB, Akainu, Aokiji etc can fight for several Days ( akainu vs aokiji 10 days ) ( roger vs wb 3 days etc), what's 20 minutes compared to that, people really making out of everything a feat considering Kaido fought the scabbards before and he's pretty worn out by the time he got to 1v1 Luffy and he still won.