one-horse race

plural one-horse races

1. informalhobbiesA horse race in which a single horse takes such a considerable lead that the other horses are no longer contenders to win.

   Sinister Minister . . . kept extending his lead and turned the stretch run into a one-horse race.

   2006 April 16, Bill Finley, “Sinister Minister Joins Baffert's Derby Stable”, in New York Times, retrieved 26 Jul 2014

   1 more example

   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.

   1927 June 13, “Sport: Again, McAtee”, in Time, retrieved 26 Jul 2014

2. broadlyidiomaticAn 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.

   The dominance of the men in yellow over the past decade turned international cricket into a one-horse race.

   2011 March 13, Shehan Karunatilaka, “How cricket saved Sri Lanka”, in The Guardian, UK, retrieved 26 Jul 2014

   2 more examples

   Although Mr Balladur is far ahead in the opinion polls, the spring election is far from being a one-horse race.

   1995 January 19, Andrew Marshall, “Balladur takes first step to presidency”, in The Independent, UK, retrieved 26 Jul 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.

   1998 April 5, Robert D. Hof, “Commentary: JAVA can be a contender—If Sun lets it”, in Businessweek, retrieved 26 Jul 2014