Callum McGregor was the matchwinner as Celtic beat Zenit.
The Celtic January arrivals have had more of an effect on the squad than simply bringing their own footballing qualities to the team.
The 25-year-old has been out of action for Celtic for a number of weeks, recovering from a shock hernia operation.
Former Rangers midfielder Charlie Adam has praised two Celtic stars after their win against Zenit.
Celtic face Zenit on Thursday night in the Europa League.
Celtic return to European action this Thursday when they host Zenit St Petersburg at Parkhead.
The Celtic star does not want to talk about the treble again just yet, but could not help himself when reminiscing about last year's Scottish Cup final.
The former Celtic player believes the numerous loan signings from down south is hampering the development of Scottish youngsters.
Celtic winger Scott Sinclair scored at the weekend.
Celtic have signed only two players so far in the January transfer window.