"I was very frustrated," Pulisic said after the match in an interview with CBS Sports. "There's not much else to say. I wanted to play from the beginning, as I always do. I've had to continue to prove myself, over and over again.
Pulisic has made a U.S. record 48 appearances in the Champions League -- 22 with Borussia Dortmund, for which he debuted four days before his 18th birthday, and 26 for Chelsea -- and he will be playing in American record eighth straight season in the Champions League. AC Milan hosts Newcastle United on Tuesday though he was expected to start the game on the bench in favor of Samuel Chukwueze after a poor outing in Saturday's Milan derby.
Gio Reyna is still only 20, but he has already played in three UEFA Champions League seasons and would have played in a fourth but for being injured in September 2021 and missing all of Borussia Dortmund's 2021-22 Champions League campaign.
He has not played for Dortmund since the final day of the 2022-23 Bundesliga season, suffering a broken tibia in the USA's 2-0 win over Canada in the Concacaf Nations League final in June.
Reyna did not dress for BVB's 4-2 win at Freiburg on Saturday, but he is in Paris for Tuesday's Champions League opener against Paris St. Germain.
PSG was the opponent for Reyna's debut at the age of 17 in February 2020 when he came off the bench at the Signal Iduna Park to set up fellow teen Erling Haaland for the winning goal in a 2-1 win.
Sergino Dest, 22, should begin his fifth straight season in the Champions League on Wednesday when PSV plays at Arsenal. PSV will be Dest's fourth different Champions League team after Ajax, Barcelona and AC Milan, all former champions.
PSV, which won the 1988 European Cup, will have three Americans in its team, having also acquired Ricardo Pepi, 20, and Malik Tillman, 21, this summer. Pepi has never played in the Champions League, but Tillman has previous experience at Bayern Munich (which still owns his contract) and Rangers.
At least nine Americans have played in the group stage of the last three Champions League seasons.
That number would have likely been met this fall, but Belgian champion Royal Antwerp failed to register left back Sam Vines due to what it acknowledged was an "administrative error."
Of the four other Americans registered for the group stage, Yunus Musah (AC Milan), Cameron Carter-Vickers (Celtic) and Brenden Aaronson (Union Berlin) all played for the USA at the 2022 World Cup.
Carter-Vickers (who is expected to return to action in early October) and Aaronson have both played one season in the Champions League -- Aaronson's 714 minutes with Salzburg in 2021-22 are the second most by an American in a single season -- but Musah will be making his European debut.
The fourth player is 17-year-old goalkeeper Diego Kochen, who is expected to start for the USA at the 2023 Under-17 World Cup -- if he is released by Barcelona. He has made the Barca first team as its No. 3 keeper.