His next tournament was the 2010 Serbian Open, where he was the second seed behind defending champion, tournament host and world no. 2 Djokovic. Isner advanced to the first clay-court final of his career, third final of the year, and fourth final of his career. In the final, he lost to Querrey, despite having a match point; this was the second consecutive final Isner lost to Querrey after serving for the championship. However, Isner's finals performance improved his ranking to a career-high no. 19.