Celtic tightened their grip on the Premiership title yet further with a 7-0 thrashing of second-­bottom St Johnstone at Parkhead. Goals from Reo Hatate, Giorgos Giakoumakis and Daizen Maeda gave the relentless home side an ­unassailable interval lead. Josip Juranovic added a fourth from the spot early in the second half and Matt O’Riley scored twice in three minutes before fellow substitute Liel Abada thrashed in a seventh as the home side ran amok. Ange Postecoglou’s side moved nine points ahead of second-placed Rangers, who face St Mirren in Paisley on Sunday with the pressure firmly on. Celtic have not lost a domestic game since a 1-0 defeat at Livingston in September and show no signs of slipping up in their bid to bring the league title back to the east end of Glasgow. The one downside for Celtic fans ahead of next week’s Scottish Cup semi-final against Rangers at Hampden Park was the sight of Giakoumakis limping off soon after he scored, but Maeda demonstrated his versatility and Kyogo Furuhashi’s keenly-awaited return is timely. The news that the Japan forward was in the squad for the first time since he aggravated a hamstring injury on Boxing Day gave the home supporters a boost, while Postecoglou started with the same team he chose for last week’s league win at Ibrox. Defenders James Brown and Callum Booth and on-loan Rangers winger Glen Middleton returned for the visitors, who were unbeaten in three matches. However, it took only eight minutes for Celtic to start their scoring spree. The visitors never really cleared their lines after goalkeeper Zander Clark saved Hatate’s close-range drive and, when the ball was recycled, the Japanese midfielder swept in a shot from 16 yards. Moments later, Clark did well to push another effort from Hatate past a post for a corner, from which Cameron Carter-Vickers headed wide, before the keeper blocked a shot from Tom Rogic as St Johnstone struggled to contain their slick-moving hosts. A second goal seemed inevitable, but the McDiarmid Park men gave Celtic a helping hand. Booth was too short with his pass back to Clark in the 22nd minute and Giakoumakis nipped in and rounded the keeper before sliding the ball over the line from the tightest of angles. Cheers soon turned to concern when the Greece striker went down with an injury and he had to be replaced by winger Abada. Maeda moved into the middle and, in the 36th minute, when Jota swung a right-footed cross into the six-yard box from wide on the left, the Japan attacker headed past Clark. It was all too easy for the Parkhead side. Davidson brought on Cammy MacPherson and Tom Sang for Murray Davidson and Shaun Rooney at the start of the second half, with O’Riley on for Rogic. In the 51st minute referee Andrew Dallas pointed quickly to the spot following Sang’s ungainly foul on Hatate and Juranovic beat Clark with a well-taken penalty. St Johnstone were in some distress. Abada came close with a drive and a free-kick before David Turnbull, on for Hatate, crossed for O’Riley to send a diving header past Clark and then, moments later, he drove a shot high past the St Johnstone keeper from just inside the box. There was another huge cheer when Furuhashi came on for Jota, with James McCarthy on for skipper Callum McGregor. Furuhashi made an instant impact, his through-ball finding Maeda, and, when the ball ran on too far, Abada raced in to fire high past Clark. There was still time for several Celtic attempts to get an eighth goal before the final whistle ended St Johnstone’s misery. Postecoglou’s hailed his players following the victory. “It was a great performance and I think the score line reflected our dominance. A convincing performance for the whole 95 minutes. We’re playing really well but I have said all along that we have to peak at the right time. We are in a good space in terms of the quality of squad and all the guys are really pushing it.” Callum Davidson emphasised St Johnstone retaining Premiership status. “When you come to a place like this you can’t concede early and we were a goal-down after five minutes. We have to look beyond this and look to the next five games. It’s a huge five games for the club. We have to put this game to bed pretty quick and move on. It’s never nice coming and getting beat by this scoreline and Celtic were relentless.“