Ukraine's Elina Svitolina believes she can become world number one in 2018 despite a host of challengers for the coveted top ranking.

Svitolina, currently ranked sixth in the world, was speaking after an impressive 6-2, 6-4 win over Spain's Carla Suarez Navarro in the first round of the Brisbane International on Monday.

The 22-year-old cruised through the first set but was forced to fight harder in the second as Suarez Navarro began to find her range with powerful groundstrokes.

But the Spaniard faltered while serving at 4-5 and Svitolina was able to close out the match in just under 90 minutes.

Svitolina won five titles in 2017 on her way to a career-high world ranking of number three.

She said she had worked hard during the off-season and there was no reason why she could not win a Grand Slam or take the top ranking.

Five women held the top spot at various times in 2017 -- Serena Williams, Angelique Kerber, Karolina Pliskova, Garbine Muguruza and current number one Simona Halep.

Svitolina said her ability to raise her game to see off someone as dangerous as Suarez Navarro showed she was also capable of taking the next step.

"This match was a good example that I can play a good level of tennis, a high level of tennis," she said.

"So I will try to continue to work and to, you know, to just be focused on these kind of things.

"That's what's important for me -- and then the Grand Slam and number one is all going to come if I have my game, if I'm healthy, if I'm playing my best."

Svitolina will take on Ana Konjuh in the second round following the Croatian's 6-1, 6-2 win over Dutchwoman Kiki Bertens on Sunday.

A miserable run by sixth-seeded Frenchwoman Kristina Mladenovic continued when she lost to Belarus qualifier Aliaksandra Sasnovich.

Mladenovic, who has not won a match since Wimbledon, raced through the first set before Sasnovich fought back to win 1-6, 6-3, 7-5.

In other first-round matches, 2012 champion Kaia Kanepi from Estonia beat Russia's Daria Kasatkina 6-2, 6-2.

Kanepi's compatriot Anett Kontaveit beat England's Heather Watson 6-0, 6-3 and Sorana Cirstea of Romania saw off American Jennifer Brady 7-6 (7/3), 6-1.

In the men's draw Matthew Ebden set up a second-round clash with fellow Australian Nick Kyrgios when he beat Frances Tiafoe of the USA 6-3, 6-2.

There was better news for the Americans when Ryan Harrison downed Argentine Leonardo Mayer 6-4, 3-6, 6-2 to book a clash with second seed Andy Murray.