The former England skipper curled home a free-kick on the stroke of half-time to level the scores after Pedro Rodriguez had fired Barca ahead, but Jeffren's 67th-minute effort sealed the victory for the Spanish side in front of over 93,000 fans.
Beckham has endured a difficult time since returning to the US after his loan move to AC Milan came to an end, and has twice been involved in heated confrontations with supporters.
The 34-year-old was again on the receiving end of cat calls and barracking from sections of the crowd in Pasadena last night, but his goal was nevertheless warmly received by the majority in the stands.
Asked whether he felt the goal would help him win the supporters back, Beckham replied: "Maybe, maybe not.
"If I did then great, if not, then I'm not going to lose any sleep.
"Like I said before, I always work hard for the team, I work hard for the manager and I work hard for the fans. Sometimes it's good enough, sometimes it's not.
"But I enjoyed my goal tonight.
"There's going to be the odd reaction from a minority of people.
"But 95%, 97% of the fans have been incredible."