Debutant Arthur scored a stunning goal and Malcom converted the decisive spot-kick as Barcelona surrendered a two-goal lead but survived to beat Tottenham 5-3 on penalties following a 2-2 draw at the International Champions Cup.
Barca were cruising at half-time thanks to Munir El Haddadi and Arthur, who put the LaLiga champions in a commanding position in Pasadena, California on Saturday.
A €40million signing from Gremio, 21-year-old Brazilian midfielder Arthur curled a shot past Spurs goalkeeper Paulo Gazzaniga approaching the half-hour mark at the Rose Bowl.
Arthur's memorable strike followed Munir El Haddadi's opener 14 minutes earlier, however, Tottenham dominated the second half and scored two goals in as many minutes with 15 minutes remaining through Son Heung-min and substitute Georges-Kevin N'Koudou.
Barca, though, held their nerve in the shoot-out as debutant Malcom – who was set to join Roma before the move was controversially hijacked by the Spaniards – scored the winning penalty after Anthony Georgiou's penalty was saved.
Barca were without a number of first-team regulars, with Lionel Messi, Luis Suarez, Philippe Coutinho, Ousmane Dembele and Gerard Pique among the absentees for the club's United States tour.
Premier League side Tottenham, who crushed Roma 4-1 last time out, included two-goal heroes Fernando Llorente and Lucas Moura as well as Christian Eriksen, Son, Serge Aurier and Moussa Sissoko.
Barca controlled proceedings from the outset and they exposed Tottenham's high defensive line on numerous occasions before breaking the deadlock.
Munir – who spent last season on loan at Deportivo Alaves – lost his man at the back post and headed into an empty net from close range after Rafinha directed a header cross goal in the 15th minute.
Semedo was constant threat down the flank and the Barca full-back almost doubled the lead, with his fierce shot parried away for a corner.
Barca got their second goal in the 29th minute – Arthur teed up by Rafinha before unleashing an unstoppable shot into the far corner of the net – but there were concerns for the LaLiga champions after Denis Suarez and Gomes were forced off prior to the break.
It was a comfortable opening 45 minutes for back-up keeper Cillessen, who made a relatively routine save to keep out Eriksen's free-kick.
FULL-TIME: A dominant second-half display from our young side sees us come back from two goals down to send the game to penalties! #SpursInUSA