Don't sweat it at all. Our department went through the same thing just this year. We brought in 3 candidates for a position. Two had poor interviews, the third had a good one and got the offer, but ended up accepting another offer near hu's hometown several states away. We then brought in a 4th candidate who interviewed extremely well. While that candidate was technically the "fourth choice," it in no way speaks poorly of that person's qualifications.
We had exactly the same experience two years ago, and we *love* our new hire.