Anthony Quinn did not receive an Oscar nomination for portraying Colonel Andrea Stavrou in The Guns of Navarone.
The Guns of Navarone faced some criticism at the time of its release due to the age of many of the cast members particularly Gregory Peck, David Niven and Anthony Quinn who seemed a bit old for the roles of wartime commandos. This is noticeable when watching the film for Niven and Peck, but Quinn kinda completely gets away with it. Quinn plays one of the commandos who is a Colonel from the defeated Greek army working with the British to kill as many Nazis as he can. Quinn as he also would prove a little later in Zorba the Greek that he is completely believable as a man taking on men who are in their prime. Quinn simply has the strong commanding presence needed so even though he's technically not in his "prime" he still seems like quite the force to be reckoned with.
Quinn has his role down perfectly from his first scene where Peck's character Mallory gives Stavrou the info on what their new mission is. Quinn exudes the right menace as Stavrou accepts the assignment while at the simultaneously threatening Mallory. Stavrou is a particularly troubled man since his wife and children were killed in the war partially from the accidental result of Mallory's actions. Stavrou never reflects for long but Quinn is terrific by just wearing this history of Stavrou in his performance. The film throughout its course repeatedly states that the men are tired from the trials of the war, and Quinn easily expresses this the most effectively. For example Stanley Baker as one of the men just states that fact and never realizes it, Quinn does not dwell on this element, but rather expresses through the hard-boiled style of his performance.
Where a few of the performances in the few tend to waver a bit Quinn is rock solid in every scene. He even has some of the more tricky moments in his performance. In one Stavrou acts as though he is just a fisherman to fool the Nazis, and Quinn makes the whole trick believable through his portrayal of it. Another tricky aspect is that Quinn is given the major romance with a contact in Greece Maria (Irene Papas). This is particularly to the point in that she basically states that they should be together, and it is almost reduced to just a couple of glances. Quinn and Papas actually do make it work in simply portraying the attraction and understanding through these short reactions, and manage not to make the whole idea seem forced as it technically is as written.
The majority of this performance honestly is reactionary since it is an action film which is constantly on the move. What only adds to this is that Quinn is not given any of the semi heavy handed speeches in the film, which actually is rather good thing. Quinn though technically does well to even help with the speeches given by the other actors through his honest portrayal of Stavrou's unsaid feelings through every scene. He's particularly good when one of them suggests that he should kill he woman, and Quinn suggests the emotional turmoil in Stavrou without needing to resort to any histrionics. The nature of his role as well as the film itself keep Quinn somewhat limited but he uses what he does have well and easily excels the most out of anyone in the cast.