Leicester: Brendan Rodgers warned Leicester will have to suffer to reach the League Cup final after Kelechi Iheanacho's late goal earned a 1-1 draw against Aston Villa on Wednesday.
Rodgers' side fell behind to Frederic Guilbert's first half goal in the semi-final first leg at the King Power Stadium.
But Iheanacho came off the bench to equalise with his sixth goal in eight appearances this season.
Leicester will feel they should have won after dominating for long periods, but the team in second place in the Premier League will have to finish the job at Villa Park in the second leg on January 28.
"Overall I thought we dominated the game. Villa made some blocks and the keeper made some good saves," Rodgers said.
"Over two ties it was always going to be tough and to get to a final you have to suffer, but the boys are confident."
Rodgers has a remarkable record of advancing from his last 30 domestic cup ties with Liverpool, Celtic and Leicester.
But the last team to beat Rodgers in a domestic knockout competition were Villa in the FA Cup semi-finals in 2014-15 when he was Liverpool manager.
And Villa, whose last major trophy was the 1996 League Cup, will feel they are in pole position to reach the final after surviving a stern examination.
"I thought Leicester were the better team. We have given away a farcical goal. Ezri Konsa has got brain dazzled," Villa manager Dean Smith said.
"But we defended brilliantly at times and it will be a raucous crowd at Villa Park. I'm looking forward to it. It's all to play for."
The second leg winner will play Manchester City or Manchester United in the final at Wembley, with City leading 3-1 after their first leg at Old Trafford on Tuesday.
Leicester last won the competition in 2000, beating Villa in the semi-finals that year, and they were well on top at the start.
Jamie Vardy was back after missing three games due to the birth of his daughter and a calf injury and took the fight to Villa.
He seized Marvelous Nakamba's wayward header before testing Orjan Nyland, then saw his low drive blocked by Villa's keeper moments later.
But, having soaked up Leicester's early blitz on a rain-drenched evening in the east midlands, it was Villa who snatched the lead against the run of play in the 28th minute.
INFUSED WITH CONFIDENCE
Anwar El Ghazi was playing in an unfamiliar role up front due to Wesley's injury and Jonathan Kodjia's illness.
The winger drifted back out to the left flank to deliver a cross that landed perfectly for Guilbert, who got in front of Ben Chilwell and stabbed his volley in from close-range.
The French defender's first goal since August was Villa's first shot on target in the match.
Infused with confidence after that bolt from the blue, Smith's team were inches away from doubling their lead before half-time.
Jack Grealish's inswinging free-kick found Ezri Konsa and the Villa defender headed against the bar from inside the six-yard box.
Leicester wrestled back the initiative after the interval and Nyland alertly smothered the danger when Vardy tried to latch onto a through ball.
Tyrone Mings won header after header as Villa tried to weather the storm and when James Maddison did get past the defender with a bold burst, Nyland was on hand to make another good save.
Maddison tried again with a run onto Ricardo Pereira's pass, but the Norwegian saved at the near post.
Leicester's pressure finally told in the 74th minute.
Luiz, put in trouble by Konsa's sloppy free-kick, lost possession to Hamza Choudhury and Vardy found Iheanacho, who shot high past Nyland from 15 yards.
Vardy nearly won it in the closing minutes, but his shot rippled into the side-netting just as Leicester fans were anticipating a dramatic finale.