New Zealand are preparing to embark on one of the toughest tests in football, as they head to Mexico for their World Cup play-off first leg.
The All Whites topped their World Cup qualification group in Oceania with six wins from as many games, to earn the two-leg date with the fourth-placed nation in CONCACAF qualifying.
However, their upcoming battle on Wednesday stands in stark contrast to their most recent qualifying clash - a 2-0 win over the Solomon Islands in front of 5,600 people in Honiara.
The Estadio Azteca in Mexico City has a capacity of 105,000, is perched 7,200 feet above sea level and will be packed full of parochial Mexicans doing their utmost to distract the visiting Kiwis.
All Whites team doctor Mark Fulcher said they were prepared for the quite literal uphill battle they were set to face in Mexico.
"It's harder to breathe (at altitude), the respiratory rate changes, your heart rate goes up... essentially for any level of exercise, you are potentially more fatigued," Fulcher said.
"For athletes, the simple equation is that you will become more fatigued, more quickly and performance will drop off over a period of time."
Midfielder Leo Bertos said the Kiwis had recent experience playing at altitude and would be better for the exposure to it come Wednesday.
"We have some experience of being at altitude in recent years, which will help," the Wellington Phoenix man said.
"We know it is going to be tough but we can't be intimidated. It's a huge challenge for us."
Further disadvantaging Ricki Herbert's side is the fact that Mexico have lost one qualifying match at the venue in their history, a 2-1 defeat to Costa Rica in 2001 - which makes New Zealand's chances of taking a lead to the second leg in Wellington the following Wednesday all the more unlikely.
A draw of any calibre would undoubtedly go down as 'advantage NZ' heading to Westpac Stadium, as they aim to reach consecutive World Cups for the first time.
From the hosts' point of view, they will be hoping to reach the finals for the sixth time in succession, after disappointing their fans by not qualifying automatically from CONCACAF's final group.
They won just two games of 10 in the final stages of qualifying, to finish fourth behind the USA, Costa Rica and Honduras.
Mexico's head coach Miguel Herrera has named a squad of only local-based players for the intercontinental play-off, in the hope he gets some continuity from them across the 180 minutes.
The irony there being Herrera became Mexico's fourth coach in six weeks in October, as they toyed with Luis Fernando Tena and Victor Manuel Vucetich to replace Jose Manuel de la Torre, before settling on the Club America coach.
All Whites captain Winston Reid will miss the clash due to an ankle injury sustained while training for Premier League club West Ham.
Herrera must decide on who will partner Oribe Peralta up front after shunning the likes of Manchester United's Javier Hernandez in his squad as he stuck with Liga MX players only.
Peralta is set to be joined by either Aldo de Nigris or Raul Jimenez.