Celtic must hope that a sense of gratitude is one of the many qualities with which John Guidetti is blessed.

Not for the first time, they have found a Swedish striker who is lighting up their club. Guidetti is experiencing one of those spells of alchemy some forwards enjoy when it seems as if they can do no wrong, that their every touch is golden.

On the last night of the transfer window he snuck into Parkhead on loan, in the slipstream of £2.3 million man Stefan Scepovic. It's not entirely the Serb's fault that he's been overshadowed by Guidetti. They all have.

His figures simply glow. Eight goals in eight appearances now. That gives the impression of a threshing machine making mincemeat of the defences he's encountered since arriving from Manchester City but there's a lot more finesse to him than that. He swept a lovely free-kick into the net for the opening goal of this painful rout for Partick Thistle and did exactly the same from another set piece in the second half. He is a beautiful dead-ball taker who shoots with power, accuracy and style. When he was fouled in the box he was an inevitable taker of the penalty which gave him his hat-trick. He swept that home wonderfully too. The public address announcer was salivating. "Goal for Celtic," he boomed. "The scorer? Who else? John Guidetti!"

Celtic may have to rely on gratitude from Guidetti as they cling to the hope of keeping him beyond the loan which ends in May. He's playing like a boy who's thriving with the oxygen of attention and adulation. Guidetti has gone through some dark days with long-term injury and illness and Celtic have given him one of the happiest periods of his career. Will that be enough to keep him? Probably not. Dozens of richer clubs around Europe will have known about Guidetti's dormant potential and the impact he's making at Celtic is the equivalent of a flare going up alerting them that he has blossomed. City want £5 million from anyone who wants to sign him in January (he is out of contract at the end of the season). That may be too high a price for Celtic but they will face almighty criticism from their supporters if they aren't seen to make an effort. Guidetti has the Parkhead fans eating out of his hand.

"He's a good player but he had trouble in the past with clubs like Stoke and we are doing something right here," said Deila. "Celtic is a big football club and he knows that. He's started well here and I can't understand if he doesn't want to continue here. We want players who want to be here. Right now he's happy and we're happy and we will work hard to make it permanent. It's also important to understand that John Guidetti is good at Celtic, it's not just because of himself. The team is working hard for him and helping him get the right chances. This relationship has been fantastic for him from the first minute and the grass is not always greener on the other side." Guidetti agreed: "Of course the grass is not always greener," he said. "I just want to think about Saturday, not the future. When my agent comes to me and says 'listen John this is what's going to happen' then I listen to him, I have full trust in the people around me."

Fellow strikers Scepovic and Anthony Stokes are in his shadow and so too is Leigh Griffiths, who came off the bench and quickly popped in a couple of goals himself. On a night dominated by a man who can't stop scoring the other came from someone who never does. Emilio Izaguirre put away only his second Celtic goal in 170 appearances. All of it sent Celtic cantering through to the League Cup semi-final draw on Saturday evening where they could be paired with Aberdeen, Dundee United and, well, you-know-who in Govan. Guidetti remembered watching a "spicy" Old Firm game as a boy in Sweden, but was fearless about whoever Celtic will face in the semi-final. "Come Hampden Park, the 11 people standing opposite us are going down, that's the way every time we play. We want to win every single game. Especially a cup semi-final."

Partick were done for last night when Stuart Bannigan was shown a straight red card for chopping down the golden boy just before half-time, at 1-0. He took Guidetti's legs away and soon had Scott Brown, Stefan Johansen and Mikael Lustig mobbing him in angry protest. Kevin Clancy, the referee, untangled the melee and waved the red at Bannigan and he sloped off to a predictable chorus of boos.

Until then Partick had played neat, passing football. They were calm and composed, refusing to panic when Celtic gradually ramped up the pressure. They played the ball out from defence along the ground and sometimes stretched the home side's back four during a bright first half. As soon as they were down to ten men Celtic steamrolled over them, running through five goals between the 48th and 68th minutes. It was a rampage. "Having a man sent off totally changed the game," said Thistle manager Alan Archibald. "He didn't need to make that challenge. We lost silly goals, that was down to our decision-making and naivety." In this city derby, Guidetti went to town on them.