Slade, who led Yeovil to the League One play-off final at Wembley two years ago, made his first return to Somerset with his new club Brighton and looked destined to celebrate his 49th birthday with a victory as they built up a 2-0 lead.
But Yeovil showed fighting spirit in the second half and deserved a point when Scott Murray scored from the penalty spot, having already reduced the deficit to one just before half-time.
"I have no complaint about the penalty," said Slade. "I haven't seen it on the DVD but there was certainly contact there. I think that what turned the game was Yeovil's first goal right on half time. It must have changed Terry Skiverton's team talk. Up to then it had been almost too easy for us.
"Yeovil worked extremely hard as they always do and always have done but we didn't use the extra bit of class I thought we had. Little things need to be put right because little things can become big things."