home straight 
(North American also home stretch)
noun British
1The straight final stretch of a racecourse: he dominated the race in the home straight...
- The next time Royal carriages drive down the home straight at York racecourse they will be cheered on by thousands of race-goers.
- Coming into the home straight after a fast-paced race, Irish raider Helvetio moves to the head of the field and looks to be cruising.
- Kieren Fallon's mount is going well turning into the home straight of the marathon race but looks as if he cannot get a clear run.
1.1The last part of an activity or campaign: heading down the home stretch to Tuesday’s final...
- Here in America, we have entered the home stretch of the campaign season.
- With the campaign in the home stretch, what else can the candidates do to win on Tuesday?
- As the campaign enters the home straight, the struggle to gain an advantage is likely to become even more rambunctious than it has been already.