Leeds eased into the fifth round of the Carnegie Challenge Cup with a 38-18 win over Wakefield but may have lost hooker Rob Burrow in the process with a broken cheekbone.

Burrow was forced off just three minutes into Friday night's fourth-round tie at Headingley after a challenge from Wildcats loose forward Paul Aiton and will undergo x-rays to determine the exact damage.

"We don't think he's broken it but everything swelled up like he has broken it," said Rhinos coach Brian McDermott. "The little fella is in pain and he's in for a rough night's sleep."

Wakefield had their sights set on a first Cup win over Leeds for 70 years until Leeds' 20-year-old centre Zak Hardaker struck twice in 11 minutes to take his try tally to 11 in his last seven matches and further underline his exciting potential.

"I was massively worried," added McDermott. "We've got some very used bodies out there that have done a lot of game time.

"When we lost Rob, we had to put other people into different positions and have a bit of a makeshift attack in the first half. I have to give the players a lot of credit for turning things around. It was a huge effort in the second half."

Wakefield coach Richard Agar was critical of his players for letting slip a winning position with some sloppy defence in the second half.

"In the first half I thought we were excellent and a bit unlucky not to come in with a few more points on the board and a better lead," he said.

"We put ourselves in with a chance and overall I'm pretty disappointed with the second half. We knew Leeds would up the tempo and we needed to go with them.

"Leeds were a bit off in the first half and, with the amount of line breaks, we should have had more points."