Griffiths finds the target in Celtic romp
Leigh Griffiths marked his return to the starting line-up with a brilliant free-kick as Celtic took command of their second Champions League qualifier with a first-leg win.
The striker more than vindicated Neil Lennon's decision to hand him his first start for eight months seven days after making his competitive comeback off the bench following a long spell out with depression.
The Scotland international curled into the top corner from almost 30 yards to put Celtic three ahead in first-half stoppage-time.
Goals in the previous 12 minutes from Kristoffer Ajer and Ryan Christie had sent Celtic on their way to an emphatic home victory and the latter and Callum McGregor were on target during an even more dominant second-half performance.
Celtic had 26 shots at goal, 14 of them on target, while Estonian champions Kalju, who are 20 games into their league season, could not test Hoops goalkeeper Scott Bain.
Odsonne Edouard twice came close and Scott Brown forced a good save before the breakthrough came in the 36th minute when Ajer headed Christie's near-post free-kick in off the bar.
Christie won a 44th-minute penalty when Reginald Mbu Alidor handled as he flicked the ball into the box, and the former Inverness man sent the keeper the wrong way.
Griffiths had a shot diverted wide before finding the top corner with a curling effort, then punching the corner flag and sinking to his knees in celebration.
The second half was a procession of Celtic chances. Christie and James Forrest both had two strikes saved and Johnston also threatened twice before Christie curled home his second from 18 yards in the 65th minute.
Johnston forced another stop and the shots continued to rain in before McGregor drilled into the bottom corner from 22 yards in the 77th minute.