New Hibernian manager Pat Fenlon watched from the stand as his side lost to St Johnstone at McDiarmid Park.
Richie Towell's shot squirmed past goalkeeper Peter Enckelman to give Hibs the lead on 26 minutes.
But Francisco Sandaza levelled with a low shot and Marcus Haber headed Saints ahead just before the break.
Dave MacKay's free-kick stretched the hosts' lead as they recorded a first win for boss Steve Lomas in his second match in charge.
Fourth-place St Johnstone move to within seven points of Motherwell in the Scottish Premier League while Hibs remain ninth, two points above bottom club Inverness.
With Fenlon having been appointed on Friday, Billy Brown continued to take charge of the first team, although his future in the role of assistant manager remains unclear.
Saints were dealt an early blow when Cillian Sheridan, who had just returned to the side, pulled up with a recurrence of a hamstring problem and the striker was replaced by Haber.
With rain covering much of Scotland throughout the weekend, conditions in Perth were treacherous and players from both sides struggled to pick passes and create chances.
However, Leigh Griffiths lifted the malaise when he worked his way into a shooting position and forced a save from Enckelman.
Towell followed through on the rebound and, though Enckelman got something on the effort, the keeper could not stop it crossing the line.
The goal boosted Hibs and Martin Scott missed a headed chance in their next attack.
The home side tried to respond and Steven Anderson, Murray Davidson and Chris Millar also missed the target.
And it was slackness in the Hibs defence that proved to be the catalyst for St Johnstone's leveller.
Sandaza robbed David Stephens of possession, fired in a shot that smacked against the post and then converted the rebound.
And, deep into first-half injury time, Saints found themselves ahead as MacKay's cross was nodded home by Haber.
The second half was barely two minutes old by the time Saints stretched their advantage and Stephens was once again culpable.
His challenge on Davidson was penalised and MacKay's free-kick swept past keeper Graham Stack into the net.
Griffiths failed to connect with David Wotherspoon's low driven cross, when any sort of contact would likely have reduced the visitors' deficit.
More uncertainty in the Hibs rearguard presented Liam Craig with a chance but his effort was blocked.
Griffiths's replacement Junior Agogo headed over from fellow substitute Danny Galbraith's cross and Ivan Sproule's shot was saved as Hibs' chances of turning the match around evaporated.
And Haber could have grabbed another for Saints in the final minute, his thunderous shot beating Stack but not the post.