"All the pressure is on them," Lopez told Spanish sports daily Marca in an interview published on Wednesday. "We should take advantage of the fact that for once we are not seen as the likely winners."
Spain won the Davis Cup for the first time three years ago when they hosted Australia on their favoured claycourt surface in Barcelona, but they face a much stiffer task when they take on the same opponents on a specially laid grass court in the Rod Laver Arena at the end of next week.
But Lopez, who has been drafted into the team at the expense of former French Open champion Albert Costa because of his better grasscourt game, says Spain are looking to repeat the success of the unfancied French who overturned the form book to beat Australia on grass to win the 2001 final.
"They (Australia) are clear favourites once again, but it isn't that long ago that they slipped up against the French," said the big-serving left-hander.
"For me a win in Melbourne would be the most important success ever achieved in the history of Spanish sport."
The 22-year-old will partner the experienced Alex Corretja in the doubles, while French Open champion Juan Carlos Ferrero and 1998 Roland Garros winner Carlos Moya are set to lead off the singles.
The Spanish team are due to arrive in Melbourne on Wednesday with their first practice session scheduled for Thursday.
The Australians will be led by Wimbledon finalist Mark Philippoussis and former world number one Lleyton Hewitt in the singles, while Wayne Arthurs and Todd Woodbridge will play the doubles.
The final will take place from November 28-30.
