Celtic winger James Forrest scored four goals in his last appearance for Brendan Rodgers’ side.
Celtic won 6-0 in their final game before the international break, with Forrest getting on the scoresheet on four occasions.
The winger showed some brilliant finishing, as he caused St. Johnstone’s defence all kinds of problems.
And Brown said: “That result was exceptional.
“Over the 90 minutes we were back to that pressing style, James Forrest was outrageous with four goals in 30 minutes.
“We’ve had two great seasons and there has been no downs whatsoever. There is always going to be a little slump then we’ll get back into it.”
Celtic had made a slow start to the campaign, and were facing criticism for their performances, but St. Johnstone could not live with them.
The Bhoys tore about the Saints, as they silenced many of their doubters from earlier this season.
Celtic have now moved up into third place in the Scottish Premiership table, and are now within touching distance of top of the league, Hearts.
Celtic are next in action in two weekends’ time, when they take on Hibernian at Parkhead.
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