Ryan O'Neal performance here is much like the film, and one should look at it for what is which is the male side of the love story in this Love Story. Firstly and most importantly he does have terrific chemistry with Ali Macgraw, that was integral for the film. They are effective, and very realistic together really showing an honest relationship, especially since the whole film would be a failure if it all seemed at all false, but it doesn't because their properly authentic.
O'Neal and Macgraw show the evolution of their relationship very well. They begin as most Hollywood romances do being slightly antagonistic to one another. They get over this quickly though, and their instant mutual attraction is well handled by both. Their dynamic is quite interesting with her being constantly sardonic, and he being more needy emotionally. Both find the connection between the two that is there to really create the honesty in the love story.
O'Neal really shows a great strength in his performance though when he hears his she is going to die. His reaction is properly heartbreaking, as is his sad almost denial of what is happening, and eventually his acceptance of it. O'Neal is properly empathetic, and because of the honest relationship they built up to this point, this turn of events is made truly effective.
Their relationship continues along quite well, and both are extraordinarily effective in showing how they mature as a couple, and become more connected with one another as time goes on, and their relationship goes further along. They certianly have just an abundance of strong scenes together because they always bring out the true emotions including the scene of the famous(or infamous) line after they had a fight. The line alone sounds incredibly stupid, and perhaps it is, but in context of the film it works, because of their relationship simply works.
O'Neal performance also is slightly risky in that he does in fact play Oliver as a bit of a fancy boy in the manner he speaks, but it actually does work. O'Neal never really forces his emotional manner, or suggesting the upper class breeding of Oliver, he just brings it about quite naturally. O'Neal whole performance is quite effective actually, it is not an overly complex performance, but it is a heartfelt and truthful performance throughout the film.
