Neil Warnock advised Aberdeen to give a new manager time to assess the squad before the summer before stepping down immediately after leading the Dons to Hampden.
Warnock’s departure was announced soon after a 3-1 home victory over Kilmarnock in the Scottish Gas Scottish Cup quarter-finals.
It was a second win in eight games for Warnock – the other came against Bonnyrigg Rose in the previous round – since he replaced the sacked Barry Robson on February 5.
That appointment was designed to last until the end of the season but Warnock leaves the club 10th in the cinch Premiership, four points above the danger zone.
Chairman Dave Cormack declared in a brief statement that the search for a long-term manager was at an “advanced stage”. Neil Lennon has emerged as the favourite in recent days after declaring his strong interest in the job.
First-team coach Peter Leven could be in charge for Wednesday’s Premiership clash at Dundee though, with Warnock bowing out immediately.
Warnock said in his final post-match press conference: “I said I’d try to help them out and give them my advice. My advice is to get a new manager in as soon as possible now.
“They’re well down the line and it needs an overhaul in the summer. There’s no use waiting until then and they’ve listened to me.
“I think he needs to have a couple of months looking at the squad now in depth. Because I think to be successful – and you can be successful with the right recruitment – they need a couple of months to assess it.
“I’m glad I’ve been able to get the fans to the semi-final and we deserved it because we were superior in every department. It was a really good way to end.
“I’m disappointed I won’t lead them out at Hampden but some lucky man will come in to do that.”
Warnock described his time at Pittodrie as “up and down”. He faced questions over his future after the Dons lost 2-1 against St Mirren the previous weekend despite leading with 95 minutes on the clock.
“I didn’t enjoy last week after the St Mirren game,” the former Sheffield United manager said. “I did think: ‘What am I doing here at 75’?
“But I knew I had to be the one to get everyone going on Monday because you don’t have time to dwell.”
Warnock’s departure was planned during a meeting with Cormack and chief executive Alan Burrows on Thursday.
“We had a chat and I thought it was the right time to bring someone else in,” he said. “They’re not far away. If it’s just one game or so, Peter will be okay.
“The lads know what they’re doing now. I felt it was the right time. I wanted to win and finish like that.
“That was the situation on Thursday. I told them how I felt and we’ve left amicably.”
Warnock will now possibly spend time at his holiday home in Dunoon and stated he might go to watch Morton in their quarter-final against Hearts on Monday, while he promised the Aberdeen players he will go to Hampden “for the final”.
But he would not rule out one last job, having come out of retirement last season to steer Huddersfield away from relegation danger.
When asked if this was the end, he said: “I’ve just been asked that and I said, ‘look, it’s the 16th time I’ve retired now’. I would say yes but who knows, when you get to my age you don’t know what’s around the corner – you just hope that you keep living.”
Jamie McGrath opened and closed the scoring and Graeme Shinnie netted on a day of mixed emotions for the captain – he picked up a late yellow card for dissent which will rule him out of the semi-final.
Danny Armstrong pulled a goal back for Killie late in the first half but they could not carve out any second-half chances.
The visitors missed winger Matty Kennedy through injury and could not bring on Kevin van Veen after the striker experienced a tight hamstring during the warm-up.
Manager Derek McInnes said: “We had a brilliant crowd here, expectations have been raised, but we never met that expectation and sometimes that’s the way it goes.”