The phrase "to win the position" means to succeed in being chosen for a specific job or role. It means that someone has outperformed others and has been selected as the most suitable candidate for that particular position. Full definition
They face a side who have won on just three of their previous 19 visits and have lost 29 points from winning positions against them. (arsenalfcblog.com)
Every one of the cars has been in a potential winning position in every round. (corvetteracing.com)
These traders also tend to sell winning positions too early, resulting in potentially large opportunity costs. (traderhq.com)