He said: "He has joined in training again with a huge smile on his face. David has also had a chance to see what we are really capable of recently.
"He may have had some doubts about the quality of the team initially but he has seen a very different picture in the last six games.
"He has seen us fight and scrap for results and seen that we don't give up and we are a pretty good team once we get everyone healthy. Now it all comes down to the last two games."
Beckham's efforts in training have impressed Galaxy skipper Landon Donovan, who said: "He gets into tackles, he's sprinting and cutting, so he looks great to me. Last week he was a little more ginger."
Tonight's showdown pits the Galaxy against ex-Aston Villa hitman Juan Pablo Angel, who scored twice in New York's epic 5-4 win over the Galaxy in August, when Beckham set up three of his team's goals.
Angel is the league's top scorer with 19 goals in just 23 games.