Defending Commonwealth Games squash mixed doubles champions Donna Lobban and Cameron Pilley couldn't believe it when they were seeded sixth in Birmingham.

The top four seeds earn a bye through to the round of 16, but landing in the five-to-eight range meant the Australians had to enter the competition in the round of 32.

After cruising to an 11-6 11-4 win over Papua New Guinea's Amity Alarcos and Feonor Siaguru, the pair said they had a point to prove.

"We were definitely surprised seeing us at the 5-8 seeds, at number six," Pilley said.

"We thought being defending champs and no-one's really beaten us for probably five years, that might hold us in some good stead there.

"But they've gone off the world doubles few months ago, which we didn't play in.

"So it's a funny one being defending champs but not being seeded. But definitely a point to prove."

The cousins were adamant they could defend their title.

"We're defending champions but the same time, we're not seeded to make it that far," Lobban said.

"So we feel like we've got nothing to lose."

Lobban has one fixture circled: a potential quarter-final against her husband, Scottish player Greg Lobban and his doubles partner Lisa Aitken.

"I've already started the mental warfare," she said.

On Wednesday, the PNG pair earned plenty of love from the crowd, especially when they pinched the match's opening point.

From there, it was smooth sailing for the Australians, who next play India's Joshana Chinnapa and Harinder Pal Sandhu.

On the other side of the draw, Zac Alexander and Rachael Grinham, the opening ceremony flagbearer, also progressed to the last 16 with an 11-1 11-4 win over the Cayman Islands' Jake Kelly and Jade Pitcairn.

They are awaiting confirmation of their next opponent.

"We do have to play one of the top eight seeds," Grinham told AAP.

"But at the end of the day, I'm just glad we weren't on the side with our Aussie team."

Australian Associated Press