"Because it is a step up. The forwards are a bit bigger and stronger and the backs are more skilful, so it's good to see these guys doing really well - they've obviously worked really hard.
"It definitely keeps us on our toes."
Ellis confesses that until last week, he had not seen a lot of Kerr-Barlow.
"He's a really good young player. He has a good step and is a strong runner."
Ruck defence, not a strong point of the Crusaders last week, will have to be beefed up. "Hopefully we can shut him out," Ellis said.
Ruck defence is not the only area of renovation required by the Crusaders after last week. In an uncharacteristically loose start to the season, they scraped home against an ordinary Blues side and were dominated in the collision areas by their southern neighbours.
"We've talked about the breakdown area," Ellis admitted. "The Highlanders base their game around that and we knew that, but we need to shore that up and make sure we deliver good ball for our backs.
"It's more aggression. There were little technical things, like making sure we're getting low and driving through, but it's more a state of mind."
Meanwhile, deep in heartland, life at the Chiefs has been a lot more cheerful this week.
Having recovered from the twin disappointments of an opening-round loss and mounting injury toll, the Chiefs travel to Napier quietly confident they can upset the seven-time champions.
Having blitzed the Blues in a four-try first half, they have lost the element of surprise.
"It was off the back of a really strong forward performance," Ellis said of the Chiefs' resurgence. "The pack really fronted up at set-piece and around the field. They cleaned out well and that gave the backs front-foot ball for most of the game.
"They're an exciting team. The entire backline can break from anywhere. You cannot give them opportunities. We can't be giving sloppy kicks away and allowing them to counter."
Win, lose or something in between, the chances are you'll see Ellis with a grin fixed to his dial. He's no less committed than any other Crusader, but Ellis can't be accused of taking life too seriously.
"I'm really enjoying it. I'm at an age now where I've experienced a lot of ups and downs and, now, I really enjoy the challenge," he said.
"We work so hard during the week, in the off-season and pre-season. There's a lot of stress and pressure and it can be bloody tough. Your rugby career doesn't last a long time, so there's a real emphasis for me that after all the hard work I put in, I want to enjoy it while I'm out there."
The extended break after the World Cup triumph, where Ellis played a key role in the final after replacing a struggling Piri Weepu, gave him a chance to enjoy himself off the field, too.
The United States, Fiji and Australia all had the pleasure of his presence. Even then, somewhere in the back of his mind, rugby wouldn't let go altogether.
"For every beer I had in the off-season, I knew I was going to be working just as hard to get them off when training started.
"It was one of those things where I was smiling while I was enjoying a beer in Vegas," said Ellis.
"But you know very well that there's just going to be more pain you have to go through at the end."
