The former Manchester United and Real Madrid midfielder provided the winner for the Galaxy when he swung in a low corner from the left to give his side a 2-1 win over Chicago Fire at The Home Depot Center.
Beckham said he decided to have a crack at goal when he saw Fire goalkeeper Sean Johnson off his line and was happy to see the ball go just about where he wanted it to.
"I saw the goalie cheating a little out of goal and saw a gap," said Beckham.
"I knew if I put it in area, it was going to get a touch off somebody or go straight in. Luckily, it went straight in."
Beckham, who set up the first goal with a pinpoint delivery to Landon Donovan, was in some doubt for the match because of stress fractures in his back but he said he felt good for most of the 90 minutes.
"Personally, it was great. I didn't expect to play 90 minutes. With 25 minutes to go, I seemed to get a second wind," he added.