With both goalkeepers Donovan Ricketts and Josh Saunders fit and in form, the Galaxy go into the finals not knowing who they will use on Sunday.
Arena's assistant Dave Sarachan admits it is a tricky decision especially after chopping and changing the pair for the past four MLS fixtures.
"We're very fortunate to have, in our opinion, the two best goalies in the league," Sarachan said. "We'll just kind of get through each day and have to make a decision."
Central defender Omar Gonzalez is probably happy he doesn't have to make a decision as says he feels comfortable with either shot-stopper behind him.
"They're both great goalkeepers," Gonzalez said. "It shouldn't matter who is in goal. The backline has faith and trust in both of those 'keepers. They've both done well these past three years and we've just got to worry about protecting them.
"We've been doing that the whole year by not allowing that many shots and when [teams] do get chances on them, they come up big."