The Spaniard achieved his career-best rankings of World No.10 in September 2017.
Earlier in the tie, Shapovalov had won his match with a 6-4, 6-3 scoreline against Pablo Carreno Busta.
Pablo Carreno Busta overcame Serbia’s Filip Krajinovic 6-3, 6-4 to book Spain’s place in the semi-finals at ATP Cup in Sydney.
The 34-year-old did not face a break point and won nine of the last 11 games to secure the victory in 60 minutes.
Alcaraz will make his debut in the competition, and he will be joined by Roberto Bautista Agut, one of the heroes of the 2019 World Cup
The World No. 13, who did not drop a set en route to the title, was at his impressive best against the Spaniard on Sunday.
Tennis star Novak Djokovic was disqualified from the 2020 US Open in the fourth round under the most bizarre of circumstances.
Pablo Carreno Busta defeated Novak Djokovic in the US Open 2020 and the Tokyo Olympics bronze medal match.
The Serbian fell short of making it a Golden Grand Slam as he failed to win the gold medal at the Tokyo Olympics.
The Spaniard, who defeated World No. 2 Medvedev earlier in Tokyo, survived a thriller against the Serbian to clinch the bronze on Saturday.