Aston Villa were in dreamland after just 20 seconds against Man City as John McGinn finished off a sweeping attacking move with the game's opening goal, but the joy was to be short-lived for Smith's men as Phil Foden and Rodri put the champions-elect in control before the half-time whistle.
There were no more goals to be had on the day, but red cards were brandished to both sides as John Stones and Matty Cash were sent for early baths, and any fleeting hopes of Villa pursuing a place in Europe will be dashed if performances continue in the same vein.
The West Midlands outfit are currently languishing in 11th spot after losing three of their last four in the top flight, with the absence of talisman Jack Grealish continuing to affect Smith's side in the final third, and the Villans' defence are now without a clean sheet in five top-flight games.
With only two wins to boast from their last 10 Premier League fixtures - and one from their last five at home - Villa would surely accept a top-half finish at this stage, but at least they will not become embroiled in a second successive scrap for survival.
The joy of crushing victories over Chelsea and Southampton quickly died down for Sam Allardyce's West Brom at the King Power Stadium, as the Baggies fell victim to a masterclass from the reinvigorated Jamie Vardy during a 3-0 loss on Thursday night.
The 34-year-old ended his goal drought before assisting Kelechi Iheanacho for Leicester's third - by which point Jonny Evans had already headed in his side's second on the night - and survival specialist Allardyce now finds his side's chances of a miraculous escape slimming further and further.
The Baggies remain nine points adrift of safety with six games left to play, and with Sheffield United already down and out after a miserable campaign, West Brom are sure to follow in their footsteps unless Allardyce can start to work his magic again in the next few weeks.
In fact, only the Blades have endured a worse time on the road than West Brom this season, although the two away victories for Allardyce's side this season have both come since the turn of the year as they eye what could still prove to be a crucial derby win at Villa Park.
A double from Anwar El Ghazi helped Villa on their way to a 3-0 success over West Brom earlier in the season, and the Baggies travel to Villa Park yet to win a Premier League game on a Sunday this year, drawing three and losing six of their games on such occasions.
Smith should call upon Ahmed Elmohamady to fill the void left by the suspended Cash in defence, while the Villa boss has also confirmed that Grealish will miss out again in another huge blow to the hosts.
On a brighter note, Wesley could finally rejoin the squad after almost 16 months out with a cruciate ligament rupture, but the Brazilian forward would surely only appear as a substitute if he makes the cut.
Morgan Sanson remains sidelined with a knee problem, and while Ross Barkley's fast start to life at Villa has quickly become a thing of the past, he will hope to force his way into the team over Jacob Ramsey this weekend.
West Brom remain rather fortunate on the injury front, with veteran defender Branislav Ivanovic and Robert Snodgrass the only two players definitely ruled out through thigh and back injuries respectively.
Changes could be afoot following a morale-sapping defeat at the King Power, with Callum Robinson's place at risk after he lasted just 45 minutes of Thursday's encounter, so Conor Gallagher will hope to earn a start.
Aston Villa possible starting lineup:
Martinez; Elmohamady, Konsa, Mings, Targett; McGinn, Luiz; Traore, Barkley, El Ghazi; Watkins
West Bromwich Albion possible starting lineup:
Johnstone; Furlong, Ajayi, Bartley, Townsend; Pereira, Yokuslu, Gallagher, Maitland-Niles, Phillips; Diagne
We say: Aston Villa 1-2 West Bromwich Albion
Villa's second half of the season could have panned out a whole lot differently had Grealish not entered the treatment room, but Smith's side are a team low on confidence right now.
It may be too late for Allardyce to pull off one of his survival miracles now, but his side can turn up the heat when it matters most and a derby should give West Brom an added incentive to secure a shock win, and we can see them doing just that.
Watch the Sports Mole Football Shorts prediction for this game below: