Brad Jones has observed very few weaknesses in Simon Mignolet's game since the stopper completed a switch to Liverpool last month and warned that the goalkeeper has not reached his peak yet.
After sealing a transfer to Anfield during the final days of June, Mignolet kicked off pre-season training at Melwood alongside new colleague Jones and made an instant impression on his fellow custodian.
"I've seen a fair bit of him and he's done really well. Last season was probably his best so far and Sunderland probably owe a bit to him for staying up," Jones told Liverpoolfc.com.
"He probably produced a few points for them over the course of the season. For him, it's a big move but it's something he's probably deserved from last year. He'll be hoping to continue in the way he finished last season.
"His best quality is his overall quality. He's pretty consistent in everything he does. That's where you want to be - be good at every aspect, really.
"Last year he was very consistent and he probably doesn't have many weaknesses. He's got a few years before he hits his peak as well. He's a very good goalkeeper.
"It doesn't change too much for me. It's a new challenge, it's someone new. Simon's come in, he's a great guy, good to work with and a good goalkeeper.
"Training has been good and it's just about getting on with it and doing your best, as you do every day. At the moment, training is really enjoyable and hopefully it continues that way."
Double sessions were the order of the day when pre-season preparations got underway at the beginning of the month, and the hard work has continued during the club's summer tour of Indonesia, Australia and Thailand.
"It's tough but that's what we all expect from pre-season," the Australian reflected. "The fact we've got a full squad together now is a bonus and the boys are keen to crack on and get on with what is in front of us.
"Everyone has the mindset of what pre-season is all about and you know it is going to be hard work, so it's just about getting through it and making sure we're ready for the first game of the season."