The Chiefs will have a home Super Rugby Pacific semifinal, but are likely to be without star No.8 Wallace Sititi, who suffered a head injury in their 46-24 win over Queensland Reds.

In a freak occurrence, Sititi copped a double headknock midway through the first half and play was paused for a long period, while he was treated on the ground by medical staff.

He was conscious when leaving the ground on a medicart, before being taken to hospital.

Sititi had been hit high in a tackle by Reds loose forward Lukhan Salakaia-Loto, but almost instantly suffered a second headknock in a collision with one of his own teammates.

He was clearly in distress on the ground and was groggy when he attempted to stand. There was a delay of about six minutes, while he was attended by medics.

Salakaia-Loto was given a yellow card, but it wasn't upgraded to red on review, with officials saying Sititi dipped into the tackle and the main damage was done by the collision with his teammate.

Next Friday, the Chiefs will host a semifinal against the Crusaders, who saw off the Blues 52-31 earlier.

Under the competition's "lucky loser" concept, the Blues get another chance and will take on the in-form Hurricanes in Wellington, meaning the semifinalists are all New Zealand teams.

The Reds put forward a spirited effort, contesting everything with vigour, before the Chiefs' class saw them take control midway through the second half.

In a welcome return from injury, first-five Damian McKenzie scored two tries in a 26-point haul overall.

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Footage showed Sititi rolling into the recovery position before visibly shaking on the ground, with the Chiefs leading 8-7 at the time of the incident.

The teammate he collided with was identified as Chiefs prop Sione Ahio, with referee James Doleman issuing the yellow card and the TMO ruling the major injury had been caused by the head clash with Ahio rather than Salakaia-Loto's initial contact.

McKenzie, who had been returning from a week out with concussion himself, scored two second-half tries to seal the win, including a quick tap off a penalty that caught the Reds napping in the 46th minute.

Reds skipper and Wallabies flanker Fraser McReight, playing his 100th Super match, told Stan Sport his side had given everything despite the result.

"We did throw everything into it and the fight from our group all year has been outstanding, so that's all we can ask for, and they definitely delivered that tonight," he said.

Only five points separated the teams at halftime, with the Chiefs leading 22-17, before McKenzie's class proved the difference in the second half.

— additional reporting by AAP