Challenged once more, Kei Nishikori proved he would be hard to beat at Melbourne Park.
Kei Nishikori overcame a fierce test from Ivan Dodig to reach the Australian Open third round on Thursday.
The Japanese fifth seed was forced into a fight before prevailing 4-6 7-5 6-2 7-6 (7-0) in two hours 47 minutes on Hisense Arena at a hot Melbourne Park.
Nishikori looked unsettled early against the Croatian world number 86, who mixed up his game and shortened points.
But he would eventually show his class, as he did against Nicolas Almagro in the first round, as Nishikori belted 52 winners in a high-quality affair.
A well-crafted point helped Dodig break serve in the third game, but that advantage was gone immediately.
Nishikori crushed three forehand winners in the next game, including one down the line to break straight back for 2-2.
However, a third straight break of serve followed as Nishikori committed four backhand errors.
The backhand wing was causing Nishikori problems.
He sent one long - his ninth unforced error of the set - before a Dodig serve-and-volley saw the Croatian into a 5-3 lead.
A tough hold from Nishikori saw him force Dodig to serve it out, and the latter dug himself out of a 0-30 hole to take the set.
Nishikori was left to rue 12 unforced errors, seven off the backhand side, as Dodig came to the net and attacked regularly.
Dodig shortened points when possible, with long baseline exchanges suiting his opponent.
Both players were relatively comfortable on serve in the second set, before Nishikori broke to 15 - a dead net cord favourable on one point - to take it 7-5.
A Dodig backhand into the net set up another chance for Nishikori in the fourth game of the third set, converted when the former's forehand went well long.
Nishikori's level, particularly his serve, lifted, highlighted by hitting 14 winners and just three unforced errors in the third set.
Dodig was solid, but his first-serve percentage dropped to a poor 47 per cent as Nishikori broke twice in the third set.
But just as Nishikori looked in control, Dodig broke for a 2-1 fourth-set lead.
However, serving for the set - Dodig faltered.
He found himself 0-30 down and, while he dragged himself back to parity, Nishikori passed him at the net to break back for 5-5.
Dodig, infuriated by a crowd member calling one of his shots out when it was in before he missed an overhead, saved a match point in the 12th game.
But the tie-break went Nishikori's way in convincing fashion as he fought his way through.