It will be a battle of the 20-year-olds in the Indian Wells Masters final after Japanese sensation Naomi Osaka crushed world number one Simona Halep in straight sets.

Halep was the overwhelming favourite but the three-time grand slam finalist was outclassed by hard-hitting Osaka 6-3 6-0 on Friday.

Osaka – who eliminated five-time major winner Maria Sharapova in the opening round – was not overawed against an error-prone Halep as she reached her maiden Premier Mandatory decider after just over an hour on court.

The shock victory set up a meeting with fellow 20-year-old Daria Kasatkina following the Russian's win over Venus Williams.

Halep and Osaka met at the Australian Open in Melbourne, where Halep improved to 3-0 against Osaka thanks to a straight-sets win at Melbourne Park in January.

But it was not as straightforward for Halep – who had not faced a seeded player heading into the semis – on Friday as Osaka's brute power proved troublesome for the Romanian star.

Osaka stormed out of the blocks in the opening set, breaking in the second game for a 2-0 lead.

Halep, who only won 33 per cent of her second serves in the first set, slowly found her rhythm – hitting some impressive winners to level the contest at 2-2 and 3-3.

But it was nothing compared to Osaka, who continued to respond to everything thrown at her as she broke again for a 5-3 advantage before serving out the set.

It was a similar story in the second set, Osaka – like she did in the first – getting on top early, going up a double-break against a clearly unsettled Halep.

Halep continued to record unforced errors – 27 in total while she only converted one of seven break points – as the Australian Open runner-up bowed out with a second-set bagel, despite saving two match points.