With 2016 soon upon us, here are 10 young players, aged 21 or under, to keep an eye on over the course of the upcoming year.
Gianluigi Donnarumma, 16, Goalkeeper, AC Milan
Gianluigi Donnarumma became the youngest starting goalkeeper in the history of Italian football when he made his AC Milan debut at 16 years and eight months old in their 2-1 win over Sassuolo in October. A string of solid displays thereafter have seen this confident and physically imposing custodian retain his place ahead of a pair of far more experienced colleagues. If he can continue his form into 2016 and keep his composure when mistakes are inevitably made, we could be looking at one of the future all-time greats.
Andreas Christensen, 19, Centre-back, Borussia Monchengladbach
Andreas Christensen joined Borussia Monchengladbach on loan for the 2015-16 season after impressing in the Chelsea Under-19 side that lifted the UEFA Youth League trophy in April. After a slightly shaky start, this strong centre-back, already twice-capped by Denmark, has begun to show why he is so highly rated back at Stamford Bridge. He still has plenty of experience to gain but further good performances could see him return to West London sooner rather than later.
Almamy Toure, 19, Full-back, AS Monaco
Almamy Toure has quickly established a good reputation for himself since making his Monaco debut back in February and will hope to make the team's right-back slot his own during 2016. Strong and proactive in his defensive work and a powerful forward runner in possession, he has taken impressively to a position in which he had little previous experience. The Malian's wonderfully taken second goal in the 3-3 draw with Marseille in November certainly belied his history as a centre-back.
Ruben Neves, 18, Defensive midfielder, FC Porto
Ruben Neves was just 17 when he made his debut for FC Porto, and with his 19th birthday now on the horizon this composed, positionally astute and technically able passing midfielder now looks capable of holding down a regular spot in their starting XI. His performance in their home win over Chelsea in the Champions League showed why a number of Premier League clubs are keeping close tabs on his progress, while a solid display on his Portugal debut in November suggested a spot at Euro 2016 could still be his.
Viktor Kovalenko, 19, Central midfielder, Shakhtar Donetsk
Viktor Kovalenko has consistently impressed on his way up through the youth ranks at both club and international level and played an important role in Shakhtar Donetsk's run to the final of the 2015 UEFA Youth League. An energetic, box-to-box midfielder with good movement and a keen eye for goal, he was promoted to the first-team squad at the start of the current season. His appearances to date have largely come as a substitute, but that could well change over the course of 2016.
Marco Asensio, 20, Attacking midfielder, Espanyol
Real Madrid beat off fierce competition to sign Marco Asensio from Mallorca in January. He was named the player of the tournament as Spain lifted the European Under-19 Championship in July and then made a strong start to his loan at Espanyol before tailing off a little towards the end of 2015. The departure of Sergio and arrival of Constantin Galca as manager and a more attacking approach to the Espanyol bench could, however, see this quick and incisive attacking midfielder make a more sustained impact during 2016.
Dani Ceballos, 19, Attacking midfielder, Real Betis
Dani Ceballos impressed during the second half of last season as Real Betis secured their return to the top flight at the first time of asking. Ceballos then played an instrumental role in Spain's triumph in the European Under-19 Championship in the summer. Contract issues limited his early-season minutes back in the Primera, but he has been a more regular part of the side over the last couple of months, with his on-ball ability and desire to take on creative responsibility shining brighter than the histrionics that occasionally accompany them.
Gaston Pereiro, 20, Attacking midfielder, PSV Eindhoven
Gaston Pereiro struggled with the language barrier during his first couple of months at PSV Eindhoven following his summer move from Nacional in his native Uruguay, but a superbly taken double against Ajax and an impressive substitute appearance against Manchester United in the Champions League underlined the clear potential of this multi-talented attacking midfielder or forward, whose strength, intelligence and finishing ability are likely to see him enjoy a good 2016.
Goncalo Guedes, 19, Forward, Benfica
Goncalo Guedes was promoted to the Benfica first-team squad in the summer and has since produced a series of impressive showings in both domestic and European competition. His goal and excellent display in the away Champions League win over Atletico Madrid displayed the pace, strength and intelligence that saw Portugal head coach Fernando Santos hand him his senior national team debut in November. If he can carry his current form into the New Year and beyond, a place in Portugal's squad for Euro 2016 could be within reach.
Breel Embolo, 18, Striker, FC Basel
Breel Embolo is a quick and athletically-built striker whose performances and goal return over the last 18 months have attracted the attention of a number of Europe's biggest clubs. The following year will be a busy one for the 18-year-old, with league and Europa League commitments for FC Basel in addition to the possibility of him representing Switzerland at Euro 2016. Impressive displays could result in a big move for him next summer.