The 5 youngest players to play in the Champions League

On Sunday, Gianluigi Donnarumma became the youngest goalkeeper in Serie A history at 16 years and eight months when he made his debut for seven-time European winner AC Milan.

Five days earlier, Porto midfielder Ruben Neves became the youngest player to skipper a side in the Champions League at 18 years and 221 days.

While the kids are young, they're older than the top 5 youngest players to play in the Champions League:

1. Celestine Babayaro: 16 years and 87 days

This can serve as an argument to support an older, mature head over an excitable fledgling.

Left-back Celestine Babayaro made his debut in the Champions League less than three months after his 16th birthday, but his introduction into Europe's elite competition lasted just 37 minutes before he was sent off, making him also the youngest player to be dismissed in the tournament.

At 18, Babayaro was signed by Chelsea with whom he enjoyed a successful eight-year spell. Injuries made for an unhappy stint with Newcastle United afterward, and there have been contrasting reports of bankruptcy and working with aspiring footballers in his homeland of Nigeria since he hung up his boots.

2. Alen Halilovic: 16 years and 128 days

The Croatian, dubbed the next Luka Modric (and not just because of his flowing blonde locks), was brought on from the bench for Dinamo Zagreb in 2012, a week after he became the youngest goalscorer in his homeland's Prva Liga.

Alen Halilovic quickly established himself as one of the world's most promising talents in football, and earned a move to Barcelona in 2014. The midfielder acclimatised to Spain with a season in the B team, and this term has been loaned out to La Liga newcomer Sporting Gijon so the 19-year-old can gain more valuable experience.

3. Youri Tielemans: 16 years and 148 days

Youri Tielemans is a midfielder that has been compared to the likes of Frank Lampard and his countryman Axel Witsel.

In 2013 he became one of the youngest players to appear in the Champions League, and just over two years later he continues to develop at Anderlecht. At a club that has produced the likes of Vincent Kompany and Romelu Lukaku, this is no bad thing.

4. Charis Mavrias: 16 years and 242 days

Charis Mavrias made his bow in the Champions League during the 2010-11 group stages with Panathinaikos. The winger went on to become the club's youngest goalscorer both in Europe and in the heated derby with Olympiacos.

The move to Sunderland hasn't gone to plan, however, as he managed just 150 league minutes in his debut season for the first team. Mavrias returned on loan to his former club earlier this year, and since the summer has become a permanent fixture in Sunderland's Under-21 side.

5. Bryan Cristante: 16 years and 249 days

With AC Milan already assured a second-placed finish in the 2011-12 group stages, then-manager Massmiliano Allegri introduced Bryan Cristante from the bench against Viktoria Plzen.

Despite signing a five-year contract with the Rossoneri 15 months later, the Italian midfielder left for Benfica on a permanent deal at the end of 2014's summer transfer window.

The 20-year-old has picked up a Primeira Liga medal since his move to the Portuguese capital, but only managed five league appearances during that victorious 2014-15 campaign.