With a sprinkling of gifted youths on a spine of trusty stalwarts, Liverpool cruised past MK Dons and set up a fourth-round showdown with Arsenal. James Milner opened the scoring for the visitors before helping to double Liverpool’s lead by creating a goal for a player nearly half his age, 17-year-old Ki-Jana Hoever.

The visit of the Premier League leaders attracted a record home crowd for an MK Dons match, an attendance of nearly 29,000 representing an increase of more than 300% on the turn-out for their last match here, the 1-0 defeat against Southend on Saturday. So chants of “You’re only here to see the European champions” would hardly have been misplaced, except that none of the players who started last season’s Champions League final made the trip to Buckinghamshire. Instead, and notwithstanding the presence of six distinguished senior players, this was more like a preview of Liverpool’s future, with five of the club’s most exciting youngsters given their first starts.

Never had a player as young as Harvey Elliott – age 16 years and 174 days – begun a competitive match for Liverpool’s senior team. Here the prodigy made his first appearance since joining in the summer from Fulham, with whom he made history last season by becoming the youngest player to feature for anyone in this competition. He shone here and could have scored but twice struck shots against the crossbar.

Elliott was the most eye-catching of the teenagers in Liverpool’s front three, but 18-year-old Curtis Jones also impressed, while 19-year-old Rhian Brewster made less of an impact even if his movement hinted at the potential that he is known to have. Jürgen Klopp was eager to praise another of the debutants, 20-year-old Caoimhín Kelleher, who made an excellent late save to deny Jordan Bowery.

Liverpool’s Harvey Elliott controls the ball in the Carabao Cup clash at MK Dons. Photograph: Julian Finney/Getty Images

MK Dons, with six changes from the Southend defeat, were determined to be more than supporting cast members in the Liverpool roadshow. They nearly stole the limelight with a nice attack in the 11th minute, which ended with Conor McGrandles whacking a shot just over the bar from 12 yards. Then Liverpool took centre stage. Milner danced forward from left-back to smash a low pass across the face of goal. This looked like being Elliott’s moment to announce himself but he slammed his shot against the bar from six yards.

Undeterred, Elliott continued to down the right with skill, enterprise and an artful left foot. With one marvellous piece of play in the 26th minute he invited Milner to score but the veteran sent a plunging header inches wide.

Eventually Milner made the breakthrough thanks to a large helping of luck. When a poor clearance fell to him just at the edge of the area, his shot seemed little more than a token gesture until Stuart Moore fumbled it over the line.

The hosts tried to fight back but landed no blows, Bowery going closest with a shot off the outside of the post. Hoever soon settled matters for Liverpool with a wonderful goal. Milner created it by hanging up a cross to the back post, where the 17-year-old leapt between George Williams and Joe Walsh to head superbly into the net.

Kelleher still had to make a fine save to foil Bowery after that. Klopp attributed Liverpool’s raggedness towards the end to inexperience. “The team had a lack of rhythm and experience,” he said. “The player with the most experience and rhythm was the best on the pitch [Milner]. But it’s so important we have these games and are brave enough to use the young boys. They have to feel these situations.”

Despite a bit of late panic, Liverpool went close to making it 3-0, Alex Oxlade-Chamberlain hitting the post from long-range before Elliott curled another effort against the bar. So the 16-year-old did not get on the scoresheet but sure made an impression on his boss. “He will always be a special player for moments but his overall performance, including defence, was very good,” said Klopp.