Wilhelm Steinitz
Apart from the chess, this match was a landmark in chess organisation. It was the first event to be timed by clocks.p82 The time for each move was recorded by hand. The totals for each player could then be added. This was the first practical step taken to make sure each player had the same total thinking time available. It had always been a problem that some players took much longer than others, unfairly so. Timing also helped to keep the total time for play within bounds. Eventually, special chess clocks were designed, and the idea has spread to other two-person games such as Go.