Japan No.1 Kei Nishikori is targeting an Australian Open quarter-final berth at a minimum after a promising start to the new year.

Nishikori on Wednesday won his opening match at the eight-man AAMI Classic at Melbourne’s Kooyong, which is a warm-up tournament for next week’s grand slam.

The 23-year-old world No.17 overcame Bulgarian No.23 Grigor Dimitrov 7-6 6-4.

Last week at the Brisbane International, Nishikori gave eventual winner Lleyton Hewitt a work-out before succumbing in three sets in the semi-finals.

Nishikori’s best grand slam result was a surprise quarter-final spot at the 2012 Australian Open, which he lost to Andy Murray.

Along the way he ousted Frenchman Jo-Wilfried Tsonga.

Eyeing a top-10 ranking this year, he said that he wanted to at least equal that result.

“I think I’m a much better player now,” Nishikori said.

“I’m more confident to play.

“My goal is to go quarter-finals or semis in the slams and I feel at home here because I love to play in Australia so hopefully I can go more than semi-finals this year.”

Earlier, world No.7 Czech Tomas Berdych took some time to find his range before securing victory.

He trailed Spaniard Fernando Verdasco 5-2 in the first set but fought back to take it 7-5 before cruising through the second 6-2.

“It didn’t start well for me from the beginning but I was able to get better and I was finding the rhythm,” he said.

“I think it was a solid start.”

The tournament lost its headline act with the withdrawal of defending champion and top-ranked Australian Hewitt citing fatigue after his Brisbane International title victory over Roger Federer.

Hewitt will play world No.4 Brit Andy Murray in an exhibition match on Friday night.