"Schalk is a world-class player and is now fully fit. He has been good this season, but just a bit short of world-class," said Erasmus.
"But I think he has performed really well in the past few weeks and is getting back to his best form."
Burger scored one of the Stormers' eight tries as they showed their fans they can combine an effective kicking game with their wonderful running skills.
The Lions gave the home crowd a few nervous moments as they built up a 12-3 lead in the first-half, scoring two tries inspired by Springbok centre Jacque Fourie, but there was no stopping the Stormers once they got to grips with the game.
The response was kick-started by a try from Burger ands by half-time fellow back row man Francois Louw and lock Andries Bekker had helped to steer the home side into a 23-18 lead. The bonus point try came a minute into the second half and from there on the game became a procession.
Many of the Stormers players will meet the British & Irish Lions when the tourists face the Western Province side at Newlands on 13 June.