Rafael Nadal said "every day is an adventure" after he cruised into the Brisbane International quarter-finals on his return from a hip injury.

The Spaniard broke at the first time of asking and proceeded to secure a quick win and a place in the quarter-finals.

"I take every day like an opportunity, and tomorrow is another one," he said.

Nadal will play another Australian, Jordan Thompson, in the last eight.

Wildcard Nadal is using the tournament to prepare for the Australian Open, which starts on 14 January in Melbourne.

The 37-year-old beat Dominic Thiem in the first round and from the moment he broke Kubler to love in the second game, it was hard to see past another Nadal victory.

He broke again in Kubler's second service game and although the Australian showed some fight to get on the board at 5-1 and then force three break points in the following game, Nadal calmly saved the lot and served out the set.

"I started the match playing very well, with very good determination," Nadal said. "I tried to be aggressive from the baseline and I think it worked very well.

"I think it was a very positive match for me. Two victories after a long time being outside the professional tour is something that makes me feel good."

The 22-time Grand Slam champion was given a time violation for taking too long to return from the toilet between sets but that was as close to adversity as Nadal came at the Pat Rafter Arena.

Kubler was broken to love in the first game of the second set and Nadal - whose power and athleticism appears undiminished after hip surgery - was untroubled as he went on to victory.

"The positive thing is that the first two matches haven't been super long," Nadal added.

"Of course, I had some feelings after the first match. I mean, I have been a year without playing with the tension of a real match, so I felt a little bit some muscles tired here and there.

"In general terms, I felt good."

The quarter-final will be Nadal's first since Wimbledon in 2022.

Grigor Dimitrov is a possible semi-final opponent for Nadal after he recorded a 6-1 6-2 victory over world number 56 Daniel Altmaier of Germany, successfully following up a first-round win against Andy Murray.

Elsewhere, Great Britain's Liam Broady was beaten 6-4 7-6 (10-8) by top seed Andrey Rublev in the last-16 stage of the Hong Kong Open.