New interim Celtic boss Neil Lennon returned to Easter Road to knock his former club Hibernian out of the Scottish Cup with a 2-0 win.
Lennon left Leith in January under as-yet-unexplained circumstances and was put in charge at Parkhead until the end of the season on Tuesday following the departure of Brendan Rodgers to Leicester.
He watched his charges forge ahead in the 62nd minute with a stunning strike from winger James Forrest before skipper Scott Brown hammered in the second in the 74th minute to hand Lennon's successor, Paul Heckingbottom, his first defeat in four games.
Celtic, the first team into Monday night's semi-final draw, have won all 11 domestic games in 2019 and are on course for the domestic treble-treble.
And with the Scottish League Cup already in the trophy cabinet and as the Hoops sit eight comfortable points clear of Rangers at the top of the Scottish Premiership, the Glasgow outfit could be just two cup matches away from that unprecedented achievement, with Lennon back at the helm.
The former Celtic captain's second tenure as Parkhead manager began with a dramatic last-gasp 2-1 win over Hearts at Tynecastle on Wednesday night.
Lennon, having quickly surveyed his new squad, reinstated right-back Mikael Lustig and striker Odsonne Edouard, with Jeremy Toljan and Ewan Henderson dropping to the bench. For Hibs, midfielder Stephane Omeonga came in for Stevie Mallan.
The home side were almost caught cold in the second minute when Edouard slipped in Oliver Burke but his drive was saved by keeper Ofir Marciano with Scott Sinclair, under pressure from Paul Hanlon, failing to find the target with his shot on the follow-up.
Celtic built on that early encouragement, notwithstanding a long-distance Marc McNulty effort being easily saved by Hoops keeper Scott Bain.
A slick move by the visitors just after the half-hour mark saw Edouard race into the Hibs penalty area after taking a Forrest pass but just as he shaped to go round Marciano he lost his footing and the home side survived the scare and by half-time had worked their way back into the game.
Celtic, however, stepped up the pressure after the break.
It appeared an object was thrown when Sinclair was set to take a corner, with referee Willie Collum removing it before play commenced.
Just before the hour mark Burke went to ground at the edge of the box when challenged by Hibs left-back Lewis Stevenson but referee Collum took his time before waving play on, to the anger of the travelling support.
However, a minute later those same fans were celebrating wildly when Forrest gave Marciano no chance with a thunderous drive.
Heckingbottom immediately brought on Mallan and Marvin Bartley for Mark Milligan and Daryl Horgan but the Edinburgh side looked rattled and bereft of belief.
As Hibs began to take chances they left gaps and when former Easter Road midfielder Brown thrashed in the second from 14 yards, for his third goal in six matches, Celtic had secured yet another semi-final berth.