There can only be one winner in Sunday's Super Bowl, but for two opposing players, a bigger battle has already been won, victory over cancer.

New York Giants linebacker Mark Herzlich and New England Patriots offensive lineman Marcus Cannon have both had to deal with life-threatening illness and came through their treatments to achieve their sporting dream, a place in the biggest game in American sport.

After an outstanding season for Boston College, Herzlich was diagnosed, in May 2009, with Ewing's sarcoma, a rare form of cancer affecting bone and soft tissue.

Herzlich underwent a six-month course of chemotherapy and radiation, and he also needed surgery and a titanium rod inserted into his leg, which remains in place to strengthen his bone.

The linebacker said his aim of making it in the National Football League motivated him through the arduous treatment.

Playing football again was the goal, and that really pushed me. After six hours of chemotherapy, you're sitting there and your body just feels drained, he said. You don't want to move, but I said 'I am going to be playing football again in eight months, so I need to go and work out. I need to go ride a bike, get some cardio in.

Herzlich said he made a highlights video of his 2008 season to keep him motivated. I would put that on in the chemo room and watch it over and over again just to see myself succeeding, he said. The physical pain was intense. The pain that I would get in my leg and my lower back felt like knives being stabbed into my legs. The pain coming after the surgery where I had to get the scar tissue kind of kneaded out with massage and stuff.

That was probably the worst pain I have ever been in because they had to actually tear the muscle off the bone and tear the scar tissue away. I was screaming on the massage table, said Herzlich.

Cannon's treatment for non-Hodgkins lymphoma was less painful, but going through chemotherapy inevitably weakened him.

I still had faith I was going to get into the NFL, I didn't know if I was going to get drafted or not, but I still believed I would play in the league, he told Reuters. I was blessed not to get all the side effects that so many other people get.

Cannon entered the draft, but his illness pushed him down the list. Nonetheless, the Patriots took him in round five with the 138th pick.

After missing training camp and the early part of the season due to his treatment, Cannon was finally activated in week 10 of the season and was part of the team that beat the Baltimore Ravens in the AFC Conference game two weeks ago to secure a Super Bowl spot.

The confetti was coming down, and I sat there thinking, 'How am I supposed to feel?' It's hard to take all of this in, he said.

Herzlich returned to college football in 2010, but went undrafted. His only contract offer came from the minor United Football League, a chance he turned down to keep alive his dream of reaching the NFL.

The Giants picked him up as an undrafted free agent in July, and he featured in 11 games this season.

Herzlich said his doctors played a perfect game, but he knows he has won one of the toughest challenges anyone can face. I think it is a little bit of a miracle. It's a case of beating the odds, he said.

(Editing by Julian Linden)