Defending champion Denis Istomin was knocked out of the Aegon Nottingham Open by Damir Dzumhur in the first round on Tuesday before top seed Kevin Anderson moved into round three.

Istomin claimed the only ATP singles title of his career on the grass in Nottingham last year, but the world number 65 had very different emotions 12 months later as Dzumhur triumphed 1-6 7-6 (7-4) 6-4.

Istomin, who failed to make it through qualifying at the Gerry Weber Open last week, could only manage a first-serve percentage of 57 and Dzumhur saved seven break points to move into round two.

Just the one break in the third set was enough for Dzumhur to come out on top after winning a topsy-turvy tie-break to set up a decider.

Anderson belted down 21 aces as he recovered from losing a second-set breaker to beat Ivan Dodig 6-3 6-7 (5-7) 6-3 and move into the last 16.

Joao Sousa crashed out in the second round, with Dudi Sela claiming a 6-3 7-6 (7-3) victory over the third seed, but last year's runner-up Sam Querrey beat Ernesto Escobedo 6-4 6-4.

Alexandr Dolgopolov, Steve Johnson and Andreas Seppi were among the seeds to move into round three, while Gilles Muller, Vasek Pospisil and Fernando Verdasco also made it through.