But the difference I see between these two teams is that Sri Lanka's win is pretty much assured as they are playing at home.

Looks like it was a 'Draw No Bet' odds. It isn’t displaying the odds for draw, and the displayed odds were lower than it should be for 1×2 betting market. The weather forecast is a bit concerning as there is a good chance of rain in the remaining days. But the 1×2 betting market odds is pretty good for Sri Lanka now. I hope they will win the match.
