Brendan Rodgers warned that his evolving side would not get anywhere without learning how to suffer. Aston Villa sure put them to the test here, as they defied the form book and a spate of injuries to inflict serious hardship on Leicester. Frédéric Guilbert’s goal even looked like giving Villa a lead to take into the second leg in three weeks but Kelechi Iheanacho came off the bench for an equaliser that leaves this Carabao Cup semi-final intriguingly poised.

This was a far tighter contest than expected and nothing like the Premier League encounter a month ago at Villa Park, where Leicester sashayed to a 4-1 victory. A repeat of that would have been no surprise given the wretched luck that has beset Villa during a spell when they have lost most of their spine to injury, including Tom Heaton, John McGinn and Wesley. Their lineup on Wednesday included no specialist striker, as Jonathan Kodjia was omitted from the squad after falling ill, according to Dean Smith.

Smith improvised a solution – Anwar El Ghazi and Jack Grealish alternating as centre-forwards while the defence continued with the back three that has served them well in recent weeks – and his team applied it with enough determination and quality to make life difficult for their high-flying hosts.

Leicester appeared to have got to grips with the visitors by the 24th minute but then, suddenly, Guilbert scored with Villa’s first real attack, beating Ben Chilwell to a cross by El Ghazi at the back post to poke home from close range.

That shocked Leicester and for a while they lapsed into uncharacteristic raggedness. They were fortunate not to fall further behind before half-time, Ezri Konsa heading against the crossbar after beating Kasper Schmeichel to a free-kick by Grealish.

Rodgers used the break to correct a mistake he said he had made with his initial lineup. He introduced Hamza Choudhury in place of Dennis Praet, who had been chosen to start after Wilfred Ndidi suffered a meniscus injury in training. The Nigerian has been outstanding in midfield for Leicester this season and was sorely missed, which makes it bad news for them that he is expected to be out of action for up to four weeks.

Aston Villa players celebrate Frédéric Guilbert’s first-half strike. Photograph: Carl Recine/Action Images via Reuters

But Choudhury did well after coming on and was integral to securing almost total territorial dominance for Leicester.

“We weren’t fast enough with the ball [in the first half], the biggest problem was our pressing. We were not aggressive enough and that was down to me,” said Rodgers. “Wilf got taken out of the game at the last minute and I opted to put in another ball-player. [Choudhury] should have started.”

The newcomer added more steel but Leicester still had to summon more fluency and ingenuity to unlock the increasingly resolute Villa. When they did create openings, they would have to show more composure than Youri Tielemans did in the 53rd minute when he wafted a shot high and wide after a slick exchange with James Maddison.

Konsa, Tyrone Mings and Kortney Hause excelled in the heart of Villa’s defence, ensuring that Orjan Nyland was not as busy as Leicester’s possession suggested he should have been.

But the keeper, who had stood strong to deny Jamie Vardy before Villa took the lead, made a couple of fine saves to foil Maddison. He did a fine job deputising for Heaton, though Villa are still keen to strengthen their goalkeeping options before the close of the January transfer window, with Milan’s Pepe Reina, formerly of Liverpool, close to joining.

Nyland could not be blamed for Iheanacho’s equaliser after 74 minutes, which is it not to say Villa were faultless. “It was a farcical goal to give away,” said Smith, aghast at a sloppily taken free kick and the ease with which Choudhury nudged Douglas Luiz off the ball near halfway. Choudhury rapidly fed Vardy, who helped it on to Iheanacho, who rammed in a superb shot from just inside the area.

Leicester did their utmost to take a lead to Villa Park. Ricardo Pereira slipped Vardy through on a late counterattack but the striker fired just wide and Nyland saved a header by Caglar Soyuncu at the death.

Though outplayed for the second half, Villa deserved the draw for their resilience and organisation. Smith suggested it gave him optimism for the second leg, not to mention Villa’s fight for survival in the Premier League. “We can take an awful lot of confidence and belief away from this game,” he said. “To leave here unbeaten when everyone knows how well they have been playing is good for our confidence.”

Rodgers, too, saw much that pleased him. “It’s a semi-final and you’re not going to have everything your own way. We had to be patient and stay calm and keep playing. I thought the players dealt with that really well. They showed a great mentality. It’s well balanced. We look forward to the challenge at Villa Park.”