The Frenchman was in two-metre swells, about 400 metres offshore from the Baylys Beach entrance.
"A local boy came running up to my house as he knew I was a lifeguard. He helped me set up some gear and we loaded it into the rescue IRB," Mr Powell said.
"I'd set it up two hours before this guy got into trouble."
Together with his dad and a couple of mates they launched the IRB and searched for the man in the waves for about five minutes before spotting him.
The 23-year-old was hauled into the boat and taken ashore.
"He had given up and was completely out of energy just floating in the water. He was very lucky he hadn't ingested any water and was okay," Mr Powell said.
The visitor had been with two friends, who had made it back to shore safely.
Then on Sunday at 4pm Mr Powell's skills were again called upon after a 23-year-old local woman struck difficulty in the surf. Mr Powell's surfer mate swam out to the young woman and kept her afloat while he launched the IRB.
They got her to shore, administered oxygen and alerted emergency services.
A St John ambulance and crew arrived and initially treated the woman before calling for the Northland Emergency Services Trust rescue helicopter.
She was flown to Whangarei Hospital where she remained in a stable condition.
Having grown up on Baylys Beach Mr Powell said it was the rip currents that got people into trouble.
"Rips are the flatter water and places to stay away from. One second you are up to your knees the next up to your chest. There are big sweeping waves and strong currents."
In 2006, there were two deaths at Baylys Beach within eight days of each other.
Mr Powell is the Baylys Beach surf lifesaving patrol captain and is a member of the paid regional surf lifesaving patrols that start next Monday, December 23.
Northern region chief executive Pam Elgar said the paid and volunteer lifeguards on Northland beaches were highly skilled, but swimmers needed to take some responsibility for their own safety.
She recommended people swim between the flags on patrolled beaches, wore appropriate clothing, didn't mix alcohol with swimming and if in doubt about their competence in water to stay out.
"Beaches are a part of the Kiwi Christmas, but if it wasn't for volunteers and lifeguards like Mitchell there would be a few families without their loved ones."
Nine people have drowned in Northland waters this year.