Connor Smith netted the consolation goal for the Saints.
On a day when the fight to avoid the relegation play-off took a turn for the worst, St Johnstone was soundly defeated by a Celtic squad who had found its form again.
Ross County and Aberdeen both prevailed, which caused the Saints to fall back to 10th place and reduce their lead over the Staggies to just one point.
In Glasgow, the competition was largely one-sided.
Saints fans thought that this match might be a rematch of their early-season 0-0 draw because they didn’t concede until the 40th minute.
However, there was minimal uncertainty over the final result as soon as Kyogo placed the champions ahead.
It was somewhat of a plus that Connor Smith’s goal late on kept Saints’ goal differential from suffering.
Now that the Old Firm matches are over, Saints’ fight to survive will be decided by how well they perform against more manageably weaker opponents.
For this match, Craig Levein went back to using three center defenders, even though he had previously chosen a back four.
The game basically became one of attack vs defence, as is virtually typically the case at Parkhead.
Despite Celtic’s superiority in terms of territory and possession, Saints managed to ensure that Dimitar Mitov didn’t have to make any saves in the first part of the game.
Luke Robinson was alert to the nearest thing, which was a diagonal ball to the back post that was targeted at Nicolas Kuhn.
On the opposite side, Adama Sidibeh appeared briefly to have the opportunity to outpace Cameron Carter-Vickers, but the Perth striker’s effort was deflected outside the area by the center back.
Tempo shift
Celtic began to apply more pressure at the halfway mark of the first half, and Robinson stopped two attempts that were either off-target or very near.
The first one was examined under the VAR microscope, but it was determined that the wing-back’s arm was at his side when the goal-bound shot struck it.
But Kyogo’s close-range goal on the forty-minute mark proved to be too much for the Saints to hold out till halftime.
And 45 seconds after the restart, Kuhn’s easy finish at the back post off Kyogo’s square ball effectively ended the game.
Mitov was frozen to the spot on minute 52 as Celtic’s star player hit a beautiful shot that blasted the crossbar.
When Saints coughed up the ball, James Forrest made it 3-0 and gave the substitute freedom across Celtic Park.
After Joe Hart had denied a header from Stevie May, Connor Smith, who had replaced Matt Smith, scored a consolation goal on minute 81.
Player evaluations
Considine 6; Mitov 7; McGowan 5.5; Gordon 6.5; Carey 5.5 (May, 74); Sidibeh 5 (Kimpioka, 64); Robinson 6 (Gallacher, 64); M Smith 5.5 (C Smith, 74); Sprangler 5 (Kucheriavyi, 25); Keltjens 6.5; Phillips 5.5. No usage of Richards, Clark, or Franczak as substitutes.