The only down side to Celtic's day was a thigh injury for Hatem Abd Elhamed, whose debut lasted 50 minutes before he limped off for Anthony Ralston. The right-back will now be a major doubt for the first leg of Celtic's third Champions League qualifier against Cluj on Wednesday.

The widows of Billy McNeill and Stevie Chalmers unfurled the Premiership flag before kick-off and Celtic started their quest for a ninth consecutive title in determined fashion.

Elhamed started in a back four that was missing suspended centre-backs Jozo Simunovic and Christopher Jullien and the Israel international twice got forward to good effect in the opening stages. His low crosses provided chances for Edouard and Christie, the Frenchman well blocked by Wallace Duffy and the latter firing over.

The breakthrough came when Christie sent Johnston away with a brilliant first-time ball over the top. The winger turned Duffy one way and the other before finding the bottom corner.

James Forrest and Edouard threatened before Christie doubled the lead in the 26th minute. Saints had 10 men behind the ball but Forrest's inside pass found Christie in space 22 yards out and he stroked the ball into the top corner of the net.

Zander Clark saved from Edouard before he was fooled by the swerve on Christie's first-time strike from 25 yards on the half-hour mark after Forrest had again teed up the former Inverness man. The goalkeeper appeared to take his eye off the ball and it slipped away from his grasp.

The performance was giving the home fans the confidence to embark on an extended rendition of their 'here we go, 10 in a row' chant and Celtic continued to create chances before the break. Forrest shot wide after Elhamed's cutback before forcing a good stop from Clark, and Edouard shot into the side net after some good footwork.

The tempo dropped after half-time but Christie again lit the game up in the 67th minute. There appeared to be little danger as he exchanged passes with Johnston on the edge of the D but he fired a powerful strike in off the crossbar.

The playmaker soon went off for Ntcham but there was no respite for the visitors as the Frenchman struck in the 72nd minute. Saints defender Madis Vihmann misjudged the bounce of the ball and Edouard released Ntcham to fire high into the net.

Griffiths then set up Edouard to round a hesitant Clark and slot the sixth in the 80th minute and the Scotland striker drilled a 20-yard effort into the bottom corner six minutes later.