Nishikori exacts his revenge on Cilic

Kei Nishikori advanced to the final of the Citi Open in Washington after beating Marin Cilic in three sets on Saturday.

In what was the first match between the 2014 US Open finalists since their meeting at Flushing Meadows nearly 12 months ago, the Japanese ace trumped his Croatian rival 3-6, 6-1, 6-4 in a match that lasted just over two hours.

Much like their previous encounter, the third-seeded Cilic claimed the early advantage when he broke Nishikori's serve in the second game of the opening set.

The US Open Champion raced to a 3-1 lead and although the second seeded Nishikori had two break opportunities in the fifth game, Cilic was able to maintain his advantage and took the opener in 35 minutes.

The world number five responded well to going behind and raced to a 4-0 lead in the second set after Cilic, ranked eighth in the world, dropped his serve twice in quick succession.

Cilic nearly got one break of serve back after a marathon fifth game, which included five deuces and three break points for the Croatian, but ultimately Nishikori stood firm to force the match into a decider.

In the third set, Cilic once again found himself a break of serve down early on after falling behind 2-0. Thereafter, the match followed serve until Cilic was able level matters in the eighth game of the third set.

However, with the scores tied at 4-4, Nishikori was once again able to force his rival into mistakes at the vital moments and broke serve once more.

The 25-year-old then made no mistake when serving for the match, securing berth in the final in the US capital on his second match point.

Nishikori will face John Isner in the final after the American required three sets to see off the challenge of compatriot Steve Johnson 6-3, 3-6, 7-6 (9).

As always, Isner's serve was a huge factor in the encounter, with the eighth seed serving down 30 aces in the match, but Johnson's serving proofed just as effective.

Johnson won 91 percent of points on his first serve in the opener, but Isner was able to convert one of the two break points that came his way to take the set 6-4.

Isner was uncharacteristically off the boil in the second set, winning just 14 of 22 points on his own serve as he surrendered a break as Johnson forced a decider.

There was little to choose between the pair in the third set, with neither man able to manufacture a break point, It was Johnson who seized the initiative early in the tiebreak, taking a 6-4 advantage. However, he was unable to convert any of the three match points afforded to him.

At 9-all, Isner won the decisive mini-break and made no mistake in serving out the match at the first time of asking.