Delph, 25, was set to be out of contract in the summer and, after breaking into the England setup this season, had seen his name linked to the likes of Everton, Tottenham Hotspur and Liverpool, per the Telegraph.
It had been suggested that the midfielder was looking to move on after talks appeared to have stalled in recent months, leading to a fair amount of surprise when news of him penning a new deal until 2019 broke at the weekend.
Guzan believes keeping their star man in the West Midlands was a massive statement of intent from the club, although he could do without his constant moaning in the dressing room.
"The sky is the limit for him. If he continues to develop the way he has over the last few years it will be something special to watch,” Villa’s number one said.
"I must admit though that Fabian is a huge moaner. He moans about everything. Ask anyone!
"Sometimes he's right. Other times you're thinking: 'Okay Fabian, you're moaning just to moan here.'
“On the other side - in terms of his big personality - he's a real practical joker. He loves to have a laugh and keeps everything light-hearted, which is very important in a dressing room. You need those characters about the place.”
After his breakout 2013-14 campaign, Delph’s progress has been somewhat disrupted this season, with the former Leeds United man missing eight weeks of action with a dislocated shoulder, before picking up a straight red card in just his fourth game back.
Villa will be hoping their midfield talisman can keep himself on the pitch over the coming months, with his influential role vital to keeping out of what would be a fourth-consecutive relegation battle.