Five days after he got the winner against Hoffenheim in the Bundesliga with a shot which went through a hole in the side-netting, the striker started and completed the scoring with two legitimate efforts.
He got the German side up and running with a header midway through the first half and tapped home a fourth 19 minutes from time as it ran riot after the break.
The win moved Bayer above its Group A rival at the halfway stage, lifting it up to second place behind Manchester United on six points.
Kiessling claimed on Tuesday that the criticism he had received over Friday's incident, when his 'goal' was incorrectly awarded, had been harsh and he wanted the fuss to blow over.
He played his part in helping that happen as he gave the host side the lead with the first real chance of the match in the 22nd minute.
If Shakhtar had hopes of mounting a second-half fightback, those were dashed within 20 minutes.
And Sam added a third in the 57th minute, firing a low shot into the corner from inside the area after being found by Son.
Three became four in the 71st minute when Can's ball across from the right gave Kiessling a simple finish from close range.
Minutes later Shakhtar at last offered a threat, but