Hornets centre-back Essaid Belkalem made his World Cup debut as an 89th minute substitute in Algeria’s 4-2 win against South Korea in Group H last night.
The 25-year-old was introduced in the closing moments in place of Madjid Bougherra to help secure Algeria’s first World Cup victory since 1982.
Park-Chu young, who is still a Hornets player as his loan from Arsenal doesn’t expire until June 30, started in the game for South Korea but was replaced in the 57th minute by Kim Shin-wook - it is the first time two Watford players have played in the same World Cup match.
Algeria took the lead through Islam Slimani and Rafick Halliche then headed home their second of the game.
Abdelmoumene Djabou struck a third before Song Heung-min's strike reduced the deficit.
South Korea’s attempted comeback was halted when Yacine Brahimi added Algeria's fourth but they did score a second through Koo Ja-cheol.
Algeria take on Russia on Thursday in their final group game and know a victory would secure their place in the last 16. South Korea face Group H leaders Belgium on the same day.