"Frustration" was the word used by West Brom's caretaker boss Jimmy Shan following his side's capitulation at Villa Park on Saturday, having seen his side concede twice in the space of three second-half minutes.
To make matters worse for Albion, they lost Gayle to a couple of bookings and will now be without their 26-goal striker for this return match.
West Brom have a pretty poor 33% win rate without Gayle in all competitions this season - four wins from 12 games - compared to a 54% win rate with him in the side across 41 matches.
Shan's men had more than held their own up until substitute Hourihane produced a moment of magic from 25 yards for Villa, followed by Abraham's penalty after Jack Grealish was felled in the box.
Now, as Shan confessed after the match, it is down to West Brom to take the game to Villa.
The only previous occasion of West Brom losing the first leg of a play-off semi-final came against Swansea City in the third-tier play-offs in 1992-93, progressing 3-2 on aggregate courtesy on a 2-0 victory in the second leg on home soil.
Losing the first leg of a playoff tie at this level does not usually tend to end well. Sixteen of the last 18 sides to have lost the first leg of a Championship playoff semi-final have been knocked out - the exceptions being Derby County last season and Leicester City in 2013.
Saturday was the first time West Brom have lost the home leg of a playoff tie, in fact, previously defeating Swansea 2-1 in the third tier, drawing 2-2 with Bolton Wanderers in the second tier in 2001 and beating Wolverhampton Wanderers 1-0 at this level in 2007.
Albion have it all to do if they are to recover from their late setback at Villa Park, then, and they will have to do it without their leading marksman. Achieve that and you would not bet against the Baggies returning to the Premier League at the first attempt.
Recent form in Championship: WWDWLL
Villa boss Dean Smith admitted to being surprised by West Brom's gameplan in the first leg, expecting the opposition to be a little more gung-ho with their approach.
Only title winners Norwich City scored more goals than Albion during the regular season, but Shan's men did not push on at 1-0 up - going with six across midfield for most of the match - and Villa made them pay.
Incidentally, the Villans boast the third-best goals tally in the second tier, so it is unlikely that this one will finish goalless.
A lot was made of Villa's form heading into the first leg, with a club-record run of 10 wins on the spin lifting them into the playoffs, before taking their foot off the gas in their final two matches.
Away from home they ended the regular season without defeat in seven matches, winning five of those. Their most recent away loss came against Brentford in February.
That resilience will need to be on show when they make the short trip to The Hawthorns in midweek - a ground that Smith's men have failed to pick up a victory in seven attempts in all competitions since a 2-1 win there in the Premier League more than a decade ago.
A draw would be a good enough result to take Villa through, of course, and they will feel confident of scoring on enemy territory judging by the form of Abraham.
The Chelsea loanee has found the back of the net with four of his last five attempts on target in the Championship, including the playoffs, with each of those goals coming against different opposition (Sheffield Wednesday, Bristol City, Bolton and West Brom).
Villa fell just short with defeat to Fulham in last season's playoff final. Twelve months on, though, with a united squad, Villa seem well positioned to end their three-year wait for a top-flight return.
Recent form in Championship: WWWDLW
As for the visitors, the big decision for Smith to make is in midfield following Hourihane's display from the bench in the first leg after replacing Glenn Whelan, who made a mistake for the opening goal.
Hourihane is expected to get the nod over his Irish compatriot, while Andre Green may also have done enough during his half-hour cameo to earn a start at The Hawthorns.
West Brom possible starting lineup:
Johnstone; Holgate, Bartley, Hegazi; Mears, Brunt, Johansen, Gibbs; Phillips, Rodriguez, Murphy
Aston Villa possible starting lineup:
Steer; Elmohamady, Tuanzebe, Mings, Taylor; Green, McGinn, Hourihane, Grealish, El Ghazi; Abraham
Head To Head
Villa ended a four-game winless run against West Brom with their victory at Villa Park in the first leg.
They last won back-to-back matches against the Baggies in all competitions back in March 2015, winning 2-1 in the Premier League and then knocking them out of the FA Cup four days later.
The two regular-season fixtures between the sides finished 2-0 to Albion at Villa Park and in a 2-2 draw at The Hawthorns - Rodriguez bundling in a controversial stoppage-time equaliser for the hosts after Anwar El Ghazi struck twice for the Villans.
We say: West Brom 2-1 Aston Villa (3-3 on aggregate, Villa through on pens)
Shan may have been left disappointed by the result at Villa Park, but his side now have 90 minutes - or more - to redeem themselves. Only four points separated the sides after 46 games and we are expecting this one to go the distance, leaving it down to a battle of nerves to determine who makes it through to Wembley, where one of Leeds United or Derby County will await.