Former striker Cillian Sheridan says Celtic showed their "ruthless" side in incredible attacking display as they annihilated Hearts 7-1.

The Parkhead side looked back to their best after another chastening European defeat at Benfica on Thursday, sweeping aside last season's Premiership runners-up.

Speaking on the BBC's Scottish Football Podcast, Sheridan detailed how a two-minute spell won the game for Martin O'Neill's men on Sunday as they responded emphatically.

"Celtic were ruthless," the former forward said. "I did think before the game that Celtic would win. I didn't ever think it was going to be 7-1 or the manner that they won it in.

"One of the biggest things you could see was the value of set-pieces. Within two minutes, Celtic scored two set-pieces early on and then that was the game done.

"As soon as Celtic got up early it just allowed them to build on the momentum."

Celtic headed into the recent international break on a downer after three successive defeats, two of which came from rivals Rangers, but has their past two Premiership results - wins against Motherwell and Hearts - given some of the fans a renewed sense of optimism, despite a disappointing night on Thursday?

"I think it shows just how quickly momentum can change in not only football, but especially Scottish football," Sheridan added.