David Eagle is easily one of the strongest characters in the series, evident from the fact that he brought Mamoru Takamura to the verge of defeat, being the second person to do so after his compatriot Bryan Hawk. He was even strong enough to defeat fellow middleweight world champion Richard Bison twice, as well as earn gold for his team at the Olympics, whereas junior lightweight champion Mike Elliott only managed to get silver. Overall, this shows that David Eagle is incredibly strong even for the standards of a world champion.
David is an all around by-the-book boxer, using basic boxing techniques and strategies which are polished to the highest level. His most deadly "weapon" is a sharp, solid One-Two that coach Kamogawa has even stated to be near perfection.
Eagle is calm and calculative; he knows how to hide his strength until the right moment, and how to act overwhelmed only to bring out bad habits from his opponent. He would also use the early rounds of a bout to study his opponent, as he did in the title match against Takamura, by putting up a solid guard and in combination with his Ominous Pressure he would force an opponent take steps back without them realising, despite Eagle being the one receiving the punches. Eagle has furthermore shown incredible determination in his fights, which Takamura compared to his junior, Ippo Makunouchi.
Physically, technically, and even in terms of fighting spirit, Eagle should be considered among the handful of boxers in the series who have no outstanding weaknesses---yet halfway through his match with Takamura, Takamura discovers that Eagle's sense of "good sportsmanship" is in fact a major handicap. Eagle does not attack Takamura's bloodied eye to force a medical decision, and he seems to admire Takamura so much that he only wants a competition with him, not a victory. Takamura exploits this mentality to eventually defeat the otherwise perfect Eagle, first by bloodying Eagle's eye and then deliberately targeting it, then instilling fear in Eagle through demonstrating his own physical and technical skills, which are equally world-class.