A vacancy has arisen on the left of Liverpool’s forward line and an early, eye-catching application to fill the role has arrived from a 16-year-old. Rio Ngumoha further enhanced his first team claims with a sparkling display against Athletic Bilbao that underlined the formidable strength, and options, available to Arne Slot.

Ngumoha opened the scoring superbly and teed up a second goal for Darwin Núñez inside five minutes at Anfield in the first of two pre-season friendlies against the Basque club. A packed Anfield crowd had to wait for the second fixture to catch a first glimpse of new signings Florian Wirtz, Milos Kerkez, Giorgi Mamardashvili, Hugo Ekitiké and Jeremie Frimpong. Ngumoha kept them entertained and whetted the appetite prior to their appearances as Liverpool recorded a comfortable 4-1 win in match one.

The left winger is not eligible to sign a professional contract until he turns 17 on the 29th of this month but showed why Chelsea were livid when Liverpool tempted him away from their academy last summer. In only the second minute of his second senior appearance at Anfield the teenager, who made his full debut against Accrington Stanley in the FA Cup last season, set off from the halfway line and, with Athletic defenders all in retreat, curled an excellent finish into the bottom corner of the Kop goal from 20 yards.

Ngumoha produced something similar in Liverpool’s previous pre-season outing against Yokohama F Marinos last week. That goal came on the day Luis Díaz completed his £65.5m transfer to Bayern Munich, creating an opening on the left that could be filled by any one of Cody Gakpo, Wirtz, Ekitiké and perhaps the 16-year-old talent from London. His display was enough to prompt chants of “Rio” from the Kop and a song in his honour from the singer who appeared during the interval.

Ngumoha’s emergence – predicted with confidence by John Terry when he lamented the youngster’s exit from Chelsea – is timely for Liverpool as they await Newcastle’s next move on Alexander Isak. There may not be a rush to replace Díaz given the options already at Slot’s disposal. The Premier League champions can afford to wait on their prime target for the No 9 role and leave their £110m offer for Isak on Newcastle’s table.

Three minutes after his individual goal Ngumoha headed down a Ben Doak cross for Núñez to convert from close range. Anyone looking for clues as to Núñez’s next step – with Al Hilal interested in taking him to the Saudi Pro League – will have noted the hand-on-the-heart celebration that followed from the £60m-rated Uruguay international in front of the Kop. A glimpse of Liverpool’s past and future, perhaps. Doak and Harvey Elliott, two other players who could leave Anfield in this window, were also on the scoresheet in the first contest against Ernesto Valverde’s side. Ngumoha’s footwork and pace also impressed in the 67 minutes he was on the pitch. He received a well-earned rousing reception when replaced by Trent Koné-Doherty.

The opening game started at 5pm as scheduled despite supporters in the Main Stand having to be evacuated just over an hour before kick off due to a false alarm.

Liverpool’s first appearance on home soil since the tragic deaths of Diogo Jota and his brother, André Silva, was marked by the club’s former captain Phil Thompson and Athletic president, Jon Uriarte, laying wreaths in front of the Kop before the game. There was a moving moment 20 minutes in when everyone inside the stadium rose to their feet to applaud Liverpool’s number 20. Play stopped and players from both teams also joined in the applause for Jota and Silva.

Slot was without Virgil van Dijk for both Bilbao games due to illness. The Liverpool head coach indicated the club captain could be a doubt for Sunday’s Community Shield against Crystal Palace. Conor Bradley and Joe Gomez were also absent through injury, forcing Slot to deploy 18-year-old midfielder Trey Nyoni in central defence for the first Bilbao contest and Luca Stephenson at right-back, while goalkeeper Alisson was unavailable having left Liverpool’s recent pre-season tour of Asia due to personal reasons.

Summer signings Freddie Woodman and Armin Pecsi filled in for the first choice goalkeeper, playing one half each, while Georgia international Mamardashvili made his Anfield bow in the second game behind a central defence of Ibrahima Konaté and Wataru Endo. That is one department where the champions appear light at present. Ngumoha could add to their riches up front.