A talented all-round junior, the 19-year-old has played soccer in Uruguay, sent down cricket balls at Lord's and represented Lebanon under Brad Fittler in last year's Rugby League World Cup.

But after growing up as a Rabbitohs fan and choosing rugby league over both those sports and the 15-man game - where his cousin Michael Cheika happens to be Wallabies coach - he admits the nerves got to him a little before he ran on to make his NRL debut against Penrith on Saturday.

"It was probably the most nervous I've been for a game for a while," he said.

"The butterflies were coming in, you know, a few dumps in the toilet before the game. But it's all part of the game."

Not that it showed.

But Doueihi was immediately told after the game by his infant sister Harper - one of 50 family members in attendance - he needed to work on his kicking and defence.

The 19-year-old wrote it in his notebook to work on ahead of this Saturday's clash with Manly, but he can at least know Souths coach Anthony Seibold is a little easier to impress.

With regular Rabittohs half Adam Reynolds out with a knee injury for at least another three weeks, Seibold declared Doueihi would keep the No.7 jersey until the former NSW halfback's return.

Contrary to Doueihi's sister's feedback, he'd actually done quite well. He kicked smartly to the corners to control the tempo of the game in the first half before the Rabbitohs let the Panthers mount their comeback in the second.

"Once I was into the game I settled down easily. I took a lot of confidence," Doueihi said.

"I don't get intimidated. I played in a World Cup a few months ago against the best of the best, so I'm not worried about that."

Nor is he intimidated by having to call the shots around some of his big-name teammates.

Just a few years ago trying to pose for photos with Sam Burgess and Greg Inglis, Doueihi spent the pre-season learning to direct them around the field after one of his idols in Reynolds suffered a foot injury.

"He's pretty relaxed," Burgess said.

"He's a really intelligent young man. He enjoys the banter in the sheds.

"He's a great addition to the team and it's a great quality to have for a half that he's not fazed too much."

Australian Associated Press