Giovanni Reyna has revealed that he had never been as "physically and mentally exhausted" as he was before Borussia Dortmund's mini-winter break.
Reyna has emerged as one of the brightest young talents in European football since graduating to Dortmund's senior squad in January 2020.
The United States international became the youngest American to ever play in the Bundesliga that month at the age of 17 years and 66 days, beating the previous mark set by Christian Pulisic.
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The teenage midfielder has built on that platform to establish himself as a key member of Dortmund's first team, taking in 42 appearances across all competitions in total.