Faith in young promise yielded multiple rewards for Jürgen Klopp. A first Champions League goal for 19-year-old Curtis Jones and a commanding European debut for 22-year-old goalkeeper Caoimhín Kelleher delivered victory over Ajax, a place in the knockout stage as group winners and the precious luxury of resting creaking limbs at Midtjylland next week. The Liverpool manager made a bee-line for Kelleher when the final whistle sounded on a close but deserved victory over Erik ten Hag’s side. A well-earned bear hug ensued. The Republic of Ireland Under-21 international was drafted in for his first Champions League appearance after Alisson sustained a hamstring injury in training that could sideline Liverpool’s first-choice keeper for up to a fortnight. Unlike most other departments on the pitch, Klopp had options for the Brazilian’s replacement in goal. He favoured Kelleher over the unreassuring experience of Adrián and was repaid with an assured, composed and decisive performance from the stopper from Cork. “Kelleher? He did an incredible job. I was really happy to see how good he was and how calm he was,” said Liverpool’s manager. “He’ll sleep really well tonight or he’ll not sleep at all.” Ajax were undoubtedly wasteful, and Liverpool required only a point to progress, but two fine saves from Noussair Mazraoui plus a superb stop from the veteran predator Klaas-Jan Huntelaar two minutes from time ensured Kelleher delivered victory and a well-earned clean sheet. His European bow was in stark contrast to Ajax goalkeeper André Onana, who produced a head-in-the-hands error that enabled Jones to convert the only goal of an open and entertaining contest. Liverpool should have extended their advantage from a series of second-half raids but, with Alisson making it eight senior players currently out injured and the schedule unrelenting, this was a night for Klopp to embrace the positives. As well as his players. Neco Williams was another target for the manager’s post-match celebration following a display that improved immeasurably at right-back. “I’m very, very happy because of the way the boys threw themselves into the game and the way the kids came through,” added Klopp, “and the way Robbo played on after taking a proper knock to his ankle and Hendo did the same with a proper knock to his back.” Kelleher’s previous four appearances for the club had come in the FA Cup and League Cup. The step up did not faze him at all. Initially Liverpool’s riches in attack seemed the best protection for the young keeper as Mohamed Salah, Sadio Mané and Diogo Jota, tracked closely throughout by Edson Álvarez, unnerved the Ajax defence. But the Dutch champions grew in confidence and enjoyed far too much control in the first half for Klopp’s liking. Jones had the first two chances of the game as a result of well-timed runs to the edge of the area. The midfielder’s opening effort, from Mané’s lay-off, was too close to Onana. Jones learned his lesson and his second shot, from Salah’s lay-off, arced around the goalkeeper only to thump the post with the Cameroon international rooted to the spot. Liverpool’s thrust and threat, along with Ajax’s uncertainty at the back, proved deceptive. Onana was not seriously troubled again before the break as Ajax asserted themselves in midfield and prospered down their left flank. Ryan Gravenberch, the central midfielder, was at the heart of their improvement. Davy Klaassen forced Kelleher into his first save but was offside when heading a left-wing cross goalwards. The former Everton midfielder was inches away from connecting with another delivery from the left, from Dusan Tadic, and Kelleher tipped over when Mazraoui took aim for the top corner from almost 30 yards. Ajax’s rising menace was not the only worry for Klopp. Andy Robertson received lengthy treatment to his left ankle but was able to continue. Perr Schuurs was shown a yellow card when he upended Mané as the forward attempted to race through on goal. Ajax may have been polished and inventive in possession but lacked the clinical edge to capitalise. Klaassen, unmarked and five yards out, headed wide after a well-worked free-kick released David Neres down the left. Neres then worked his way into the area but went for glory from a tight angle with two teammates better placed. His shot sailed harmlessly into the side-netting. Minutes later, from a slightly better position, Neres looked certain to score after Kelleher impressively tipped away Mazraoui’s low drive at full stretch. This time he struck the post. The visitors contributed to their downfall at both ends of the pitch. The second half flowed end-to-end and Liverpool’s press was far more effective. The breakthrough came gift-wrapped, however. Onana completely misread both the flight of the ball and the imminent danger when Williams crossed deep into the Ajax six-yard box. The keeper came off his line but let the cross go for a goal-kick. Jones had gambled on such a mistake and, only inches from the byline, volleyed into an unguarded net. Onana produced an excellent save to tip a shot from the substitute Roberto Firmino on to a post while Salah missed several chances to double Liverpool’s advantage late on. Huntelaar almost made him pay when he powered a header from Antony’s cross towards the top corner. Kelleher reacted superbly to push away Ajax’s last chance of an equaliser. Klopp was soon on his horizon in celebration.