The 21-year-old showcased the quick feet and powerful ball carrying skills that saw him called up by Wales last year.
Baker is now pushing for another senior call with the national side this summer and after his display against Leinster it is no surprise to Rees.
"He's mesmeric," said Rees. "We've seen him come through since he was 16 and we've known he has that ability.
"Over the past 12 months he's developed into someone with an aptitude for the professional game, who knows the demands.
"He can beat someone in a metre of space and after a nervous start against Leinster he had a couple of little moments which excite us for the future.
"We have him and a whole host of young forwards coming through, plus line-breakers behind the scrum. So we feel we're heading in a decent direction.
"Dan has to be in the mix. Based on his form now and the way he's earning his spurs at regional level, I wouldn't begrudge him earning a shirt and trying to push Toby [Faletau] for the next few years."
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