It is important to note that in this list we will be examining only what we have seen in the movies and actively avoiding taking anything from the comics into consideration.
Considering that Spider-Man is the only member of the team who has not reached the age of 18, coming in at number 10 on this list is even more of an impressive feat for the MCU's youngest Avenger. There may be those who are of the opinion that Spider-Man's spot should have gone to Winter Soldier (who was a definite honorable mention on this tier list), but considering that Spider-Man managed to best both Winter Soldier and Falcon during the airport sequence in Civil War, it seems pretty clear who would come out on top in a one-on-one situation with any of the heroes not mentioned on this list. While Barnes may have more mission and fighting experience, the young Peter Parker displayed skill well beyond his years in Homecoming and Infinity War, besting Vulture and, with the help of his team, nearly overcoming Thanos himself. While Bucky may have the killer instinct Parker lacks, we have to remember that there is still always Spider-Man's unused trump card should he ever need it: instant kill-mode.
9 Captain America
There are few characters in the MCU who have as compelling of a story arc and history as Steve Rogers. Captain America embodies everything that audiences love in an altruistic hero, and although he suffers from a fundamental need to sacrifice himself for the greater good, Steve Rogers has shown that he can almost go pound for pound with the MCU's strongest. During the events of Civil War, Rogers managed to bring down Spider-Man by dropping an airplane loading dock on him. (Maybe he knew he could catch it? Maybe not?) In numerous other situations, we can see Rogers using his wit and creativity to overcome asversaries much more powerful than himself. Unfortunately, his inability to overcome heroes like Black Panther, Iron Man or Thor prevent him from being placed any higher on the list.
While there is definitely potential for the Black Panther to rank higher on future lists after we have seen him develop his ability to fight with Wakanda technology, as of right now, he sits very close to Captain America in terms of strength levels and the root of their powers. While Captain America received a synthetic Super-Solider Serum, Black Panther's prefers the organic alternative heart-shaped herb found only in Wakanda's soil. After giving Captain America, Winter Soldier and Falcon a run for their money in Civil War, Black Panther demonstrated even more of his hand-to-hand combat prowess in his own feature film against rivaling tribes and Killmonger.
In the Guardian of the Galaxy films, we have seemed Gamora pull off some impressive feats of strength and skill as a fighter. She was, after all, trained and taught by Thanos himself. In addition to her superhuman strength, she is an inherently talented fighter and often the only voice of reason amongst the Guardians. Having to constantly reign in her more eccentric and peculiar team members during their endeavors says something about her strength of character as well. Gamora also marks the point on this list where human or peak-human levels of strength are surpassed. Gamora inherently has more raw power than Captain America or Black Panther ever will.
The only thing that puts Hulk above Gamora on this list is the fact that Hulk's power comes primarily from emotion. The angrier or more desperate that Hulk becomes, the more raw physical strength he acquires, giving him the edge over Gamora, whose power does have a limit. There are few who can match Hulk blow for blow in a fight, as we have seen him slam gods and rip apart battalions of Chitauri armies.