A close thing
Definition 1 of 1
Pro Tip 1/3Outcome Uncertainty
Use when an outcome was uncertain until the very end, and it suggests a feeling of relief or surprise at the result. 
After the final whistle, fans sighed in relief; the game had been a close thing.
Pro Tip 2/3Tense Situation
Implies a tense or stressful situation where the outcome could have easily been different. 
Surviving the car accident was a close thing; a second later and it would've been worse.
Pro Tip 3/3Dramatic Effect
Can be used to describe dramatic situations in storytelling, adding excitement to the narrative. 
The hero disarmed the bomb at 1 second left—it was a close thing.