Redaction: The term "uphill battle" has become a description of any difficult task, and we should not miss the reality of the difficulties in waging such a fight. The common term follows from the accuracy of the military problem. The Amlicites not only fought an uphill battle, but they were fairly successful. Mormon gives them their credit where the credit was due. However, it is also important to note how Mormon juxtaposes the success of the Amlicites against the eventual victory of the Nephites.
Mormon's account of this battle is crafted so as to highlight the ultimate battle, which is between God and those who oppose them. As those who seek to destroy the way of the Nephites the Amlicites are godless (to Mormon). They are battling the Nephites (with God on their side). The Amlicites are fearful and worthy opponents, who are so effective in what they do that they are able to successfully wage war uphill. They are in a disadvantaged position, yet they are prevailing. In so describing the Amlicites, Mormon portrays them as militarily mighty - and perhaps mightier than the Nephites, who appear to be on the verge of losing the battle in spite of their superior tactical position.
What Mormon does with this is turn the tide of the battle not on the strategic position of the Nephites, but upon the strength of the Lord. In his words; "nevertheless the Lord did strengthen the hand of the Nephites." The tide of the battle and turned, and the Nephites are eventually victorious. Whereas the Amlicites were mighty in and of themselves, the Nephites were mighty only after the strengthening by the Lord.