A batsman who is at 99 not out and at non-striker needs 1 run to win off the last ball. How is it possible that they win the game and also that the batsman reaches his century?
I think the only way to do it is by way of penalty runs. Most straightforwardly, the batsmen could try to steal a run during the bowler's run up. As soon as they cross, the umpires would call dead ball and award 5 penalty runs to the fielding side. The batsmen return to their original ends. Now the batting side needs 6 to win off one ball. The bowler could then bowl a no ball or a wide allowing the batsmen to cross, which would score 2 runs. Now the guy on 99 is on strike with one legal ball to go and needing 4 to win.