In the latest part of our weekly #olympicthursday series profiling leading British hopes, BBC Sport's Piers Newbery speaks to lightweight double scull pair Zac Purchase and Mark Hunter.
Zac Purchase and Mark Hunter got themselves "out of a hole" when they proved they were the best in the world in a turbulent 2011 season.
After four months during which they were unable to compete together as Purchase suffered with post-viral fatigue, the Olympic champions came back and retained their lightweight double scull world title in dramatic style last September.
Reflecting on that victory last month, Hunter described the whole season as "emotionally very tough and mentally very tough".
Purchase told BBC Sport: "It was really good to prove to ourselves we can pull ourselves out of a hole when we need to. Hopefully we'll never get in that hole again."
Alarm bells sounded when Purchase's name was not among the starters for this weekend's British trials at Eton Dorney, but the decision is described by more than one person close to him as "nothing sinister" and nothing to do with last year's health issues.
"Having looked at his numbers since they came back from training camp they were a bit down, and we're talking marginally, so we've decided to focus on the World Cup series," said GB Rowing's team manager David Tanner.
"When you're dealing with very high-level guys you have to weave a slightly different path."
When fit and well, there is little doubt that Purchase and Hunter are the best at what they do.
They broke new ground for British rowing, traditionally dominated by the heavyweight men, when they won the nation's first Olympic lightweight medal with gold in the double scull four years ago, and they remain one of Britain's better bets come the Games this summer.
But with memories of last year's darker moments still fresh, and carrying the pressure of being favourites, the pair's friendship will be tested as much their nerve over the next five months.
"We get on really well," says Purchase. "The relationship has developed through the fact that our careers have been intertwined and everything improves through age.
"We get a little bit of banter going every now and then and we have a really good professional respect for each other."
However, personalities count for little in the face of performances and cold statistics once through the doors of British Rowing's Berkshire headquarters. The only thing that matters is making the boats go faster.
"When we got in a combination to start with we knew we had a lot of potential and there was a lot of excitement," says Hunter. "It was just about how far we could go and what we could achieve."
Hunter is an East End boy who loves football and learned to row at the Poplar, Blackwall and District Rowing Club on London's Isle of Dogs. He talks animatedly about a recent trip to his beloved West Ham, where he gave a motivational talk to Sam Allardyce's squad.
Purchase took to rowing on the River Severn while at school in Worcester and dreams of a chance on Masterchef. He knows nothing about football, cheerfully admitting he has no idea who Lionel Messi is.
Masterchef and Top Gear dominate Purchase's hours away from the Redgrave-Pinsent Lake in Caversham, with evenings spent trying out new recipes.
Hunter insists there is "no way" he would risk sampling any of his partner's concoctions, adding: "That's why he's sick a lot."
That gag prompts much laughter from both men but, as Purchase's withdrawal this week has shown, there is a bit more behind it than just comedy value.
"Last year was a really difficult season for me," says Purchase. "We did a lot of really hard training through the winter and it took me a long time to recover from pushing myself into the ground so much.
"We came to the trials in April and I was just knackered and out of it, so it was a case of getting into the boat and doing what we could, when we could, making sure that the progression was definitely centred around winning the World Championships rather than just winning on a day-to-day basis."
They arrived in Slovenia for the World Championships seriously "undercooked", and what followed was remarkable.
Hunter and Purchase changed tactics from their usual style of going out hard and dominating from the front, reeling in a New Zealand boat that had gone unbeaten through the whole season and edging them on the line.
"We knew that they were on form, we had a clear indication of where we were physically and what we had to play with, and we just went out and match-raced them," says Hunter. "We executed it perfectly."
A home Olympic Games would seem an obvious attraction but they have not always been a target for Hunter, who, at 33, is eight years older than Purchase.
"After Beijing I was quite content," says the Londoner. "I had achieved my lifelong ambition to become an Olympic champion; I had a great job in America coaching at UCLA, moved out to LA by the beach in Santa Monica, enjoying life.
"I had no intention of coming back and it was only after about six months I started to think about London and what it would mean to come from the area and not be part of the Olympics. That's when I started exercising again, which was gruellingly hard.
"Just putting up with Zac again has been difficult - but no, it's been great to be back. We've had a lot of success and a lot of tough times. We've proved we're a winning combination; we love racing with each other and taking on the rest of the world."
There were no such doubts for Purchase: "As soon as the Olympics were announced back in 2005 I was totally set on winning gold in London."
That target comes into sharp focus this weekend when the powerful GB squad emerge from a winter of cold, early mornings and hard work for the British trials at the Olympic venue of Eton Dorney.
Each year the whole squad has to begin again, with no-one certain of their place in a specific boat until the coaches decide, but surely there is little prospect of Purchase and Hunter being split up when the World Cup line-up is announced in April?
"From the outside, you'd say 'they've won the the Olympics, they're double world champions, they should automatically be selected', but our team doesn't work like that," explains Hunter.
"We know we're the best combination in the world; we just have to prove that we're still the top two individuals in what we do. But we're pretty confident that there's no-one that can beat us, so we're looking forward to it."
Purchase's absence this weekend will give others the chance to shine and, when asked last month about the selection process, he described it as "a case of building a bit of trust with the selectors".
The level of trust in Purchase and Hunter as a pair is evident when team manager Tanner says: "We can look at whatever we see at the trials but ideally I think we absolutely ought to see the world's leading pair in that double."
Purchase will be training over the weekend while his team-mates battle it out at Eton Dorney, but he fully expects to be there when it counts on the morning of 4 August.
"Given our results over the last few years and the reason we're both still here doing the sport, the only reason we're going to London is to cross that line first, see the flag go up, hear the national anthem and hear the crowd just go absolutely crazy," says Purchase.
"It's going to be an amazing experience, not just for us on the course but for the people watching as well. I can't wait, just can't wait."