The USA face a key week as they host Costa Rica on Friday and then visit rivals Mexico on Tuesday.
After losing to Honduras in the opening game of the CONCACAF qualifiers' final stage, in a group of six where the top three go straight to Brazil 2014 and the fourth face a play-off against a South American side, pressure has increased on Klinsmann's side.
"Every home game is a must-win situation," the German coach said.
"You want to get all the points possible in your home games."
Klinsmann will field a new-look side with captain Carlos Bocanegra left out, while goalkeeper Tim Howard, defenders Steve Cherundolo and Timmy Chandler, and midfielders Danny Williams and Jose Torres are all injured.
Costa Rica coach Jorge Luis Pinto wants to turn that USA pressure to his side's advantage.
"We will try to get control of the game and attack them," he said.
Costa Rica came from two goals behind to earn a 2-2 draw in Panama in their first match.
"We weren't focused enough in the first minutes of that game and that almost cost us the match. We can't repeat that," added Pinto.
Honduras will look to take a second win when they face a Mexico side who drew last time out with Jamaica.
Mexico captain Francisco Rodriguez said: "Honduras have now a lot of players in Europe, and that has certainly improved their level.
"We have to be very patient, as we also have great players and we will have our chances."
The other fixture features Jamaica against Panama.