Midfielder Conor Hourihane's long-range thunderbolt and forward Tammy Abraham's penalty helped Aston Villa defeat West Bromwich Albion 2-1 in the first leg of the Championship playoff semi-final on Saturday.
Jay Rodriguez was teed up on the edge of the area and it took a fine save from Jed Steer to turn the Albion striker's shot onto the crossbar.
The victor of this clash will face the victor between Leeds United and Derby County. West Brom's situation was made worse with Gayle getting a second yellow card, thus sending him off and handing him a suspension for the return leg.
John McGinn and Grealish combined for a short corner to set up Glenn Whelan, who nodded over from six yards.
The midfielder's terrible touch allowed Gayle to charge through on goal before finishing with a powerful effort.
And when it came to the spot kick, there was no mistake from the striker.
But Smith expects more from his side after they were forced to battle back from a goal down at Villa Park on Saturday.
Ahmed Hegazi was excellent as he repelled the hosts' effort and the Baggies' attacking threat relied on sporadic breaks.
Mings fired at Sam Johnstone from distance in stoppage time before the visitors were forced into a reshuffle at the break with Tyrone Mears replacing the injured Craig Dawson.
The home jitters grew along with the frustration at Albion's perceived time-wasting, with Gayle booked for delaying tactics.
Villa won a penalty four minutes later when midfielder Jack Grealish was brought down by defender Kieran Gibbs and Abraham, on loan from Chelsea, held his nerve to slot the ball in for the victor.
Hourihane entered the fray in the 70th minute, and four minutes later he got onto a finely paced Jack Grealish pass to swing a handsome shot past goalkeeper Sam Johnstone, who was left motionless in the middle of his goal.