Sam Warburton has no doubt Warren Gatland will enjoy the intensity of international rugby union again during the upcoming Six Nations after being appointed head coach of Wales for a second time.
Wales won four Six Nations titles, including three Grand Slams, and reached two World Cup semi-finals during Gatland's first spell in charge from 2008-19.
But standards have slipped since then, with Gatland returning after fellow New Zealander Wayne Pivac, his successor, was sacked by Wales having presided over a mere three wins in 2022.
Gatland's second stint begins with Wales facing world number one-ranked Ireland in their Six Nations opener in Cardiff on February 4.
France, the reigning Grand Slam champions, are also strongly favoured in a year that culminates with a home World Cup for Les Bleus.
Former Wales and British and Irish Lions captain Warburton, who played a key part in Gatland's success with both teams, said Wednesday, said while Ireland and France would be "almost dead-certs one and two", his old boss could still make a huge impact.
"What you can change is the environment, the belief and the messages that you instil in the players which can have a massive effect, particularly from someone like Warren who is held in such high regard," said the 34-year-old retired back row.
Warburton, speaking at an event organised by Six Nations Smart Ball suppliers Sage, added: "He (Gatland) will love it. He is an international coach who needs to be in the pressure-cooker of an international environment, being in the middle of the pitch in front of 75,000 people.
"That's him in his comfort zone. He has got those unflappable characteristics. It is a great asset that he has and that rubs off on all the guys."
Wales are not alone in changing their coach, with England bringing in Steve Borthwick after Eddie Jones was sacked following a dismal run of results last year.
Former Ireland captain Rory Best fears the "curveball" alterations could hamper his compatriots quest for the Six Nations title.
"It has probably brought a little bit of unknown," Best said. "If it had been Wayne Pivac and Eddie Jones you would have a fair idea of what they are going to try to do.
"From an Irish point of view, it's put in a big curveball in terms of all of a sudden two teams that you would expect to beat... as a fan now, you're not as confident."
Ireland, under coach Andy Farrell, have won 16 of their last 18 fixtures, including an historic series victory in New Zealand, although a defeat by France in Paris prevented them from winning last year's Six Nations.
Retired hooker Best, who won the championship four times, expects Ireland to be in title contention once again.
"Ireland are capable of certainly a championship and potentially a Grand Slam and it would be a massive marker to lay down with the quality of the Six Nations this year," he said.