One-Horse Race Meaning
(idiomatic, by extension) An election campaign or other competitive situation in which only one competitor is entered or in which only one competitor has a realistic chance of winning.
Example: 1927 June 13, "Sport: Again, McAtee," Time (retrieved 26 July 2014):
Since riding Harry Payne Whitney's Whiskery to victory in the Kentucky Derby, Jockey Linus ("Pony") McAtee has twice broken into the news in unconventional fashion. A fortnight ago, he won a one-horse race ("walkover") at Belmont Park, N. Y.
2006 April 16, Bill Finley, "Sinister Minister Joins Baffert's Derby Stable," New York Times (retrieved 26 July 2014):
Sinister Minister . . . kept extending his lead and turned the stretch run into a one-horse race.
1995 Jan. 19, Andrew Marshall, "Balladur takes first step to presidency," The Independent (UK) (retrieved 26 July 2014):
Although Mr Balladur is far ahead in the opinion polls, the spring election is far from being a one-horse race.
1998 April 5, Robert D. Hof, "Commentary: JAVA can be a contenderâ€”If Sun lets it," Businessweek (retrieved 26 July 2014):
A system for creating software that runs, unaltered, on all sorts of computers and devices . . . could transform the software business in the network era from a one-horse race led by Microsoft to a true contest.
2011 March 13, Shehan Karunatilaka, "How cricket saved Sri Lanka," The Guardian (UK) (retrieved 26 July 2014):
The dominance of the men in yellow over the past decade turned international cricket into a one-horse race.