Kaku leads the Red Bulls with nine assists. (Brad Penner-USA TODAY Sports)

Kaku made it official Tuesday night.

Alejandro Romero Gamarra made his debut for Paraguay, entering the match in the second half in a 4-2 loss to World Cup-bound Japan in an international friendly at Tivoli Stadion Tiron in Innsbruck, Austria Tuesday night.

The Red Bulls midfielder, who appeared as a youth international in his native Argentina, recently had his one-time international switch approved by FIFA. Kaku, who was called into Paraguay camp, has Paraguayan lineage through his parents.

Due to his call-up, Kaku missed the Lamar Hunt U.S. Open Cup match, a 4-0 win over New York City FC last week, and Saturday night’s 1-1 draw at Columbus Crew SC.

The 23-year-old Kaku leads the Red Bulls with nine assists while contributing three goals as well.

He probably won’t be available when the Red Bulls host Seattle Sounders FC at Red Bull Arena Wednesday night although he could be part of the 18 or Starting XI when the team visits the Philadelphia Union for an Open Cup match Saturday.

In Tuesday’s match, Shinji Kagawa scored one goal and created two others as Japan came from behind against the South American squad, which failed to qualify for Russia 2018.

Paraguay goalkeeper Justo Villar, 40, was replaced after 12 minutes as he made the last of his 120 international appearances before his retirement.

Japan meets Colombia in its Group H opener Tuesday, June 19.

Front Row Soccer editor Michael Lewis has covered 13 World Cups (eight men, five women), seven Olympics and 25 MLS Cups. He has written about New York City FC, New York Cosmos, the New York Red Bulls and both U.S. national teams for Newsday and has penned a soccer history column for the Guardian.com. Lewis, who has been honored by the Press Club of Long Island and National Soccer Coaches Association of America, is the former editor of BigAppleSoccer.com. He has written seven books about the beautiful game and has published ALIVE AND KICKING The incredible but true story of the Rochester Lancers. It is available at Amazon.com.