She got close enough to clinch quite a few times.. The single leg is closer, much closer than clinch takedowns. You don't need to close the distance much for it, yet not a single attempt at any form of single leg was made from erin. It wasn't just the distance management from fiorot -- it was either lack of fight iq or lack of ability by erin, or both. I don't buy that she was afraid to shoot singles because of cardio expenditure considering she had plenty of cardio left over at the end of the fight.
She either doesn't have a good single leg or she's just one of many fighters who aren't good at adapting mid fight. It is very likely that she's incomplete as a fighter at 24 years old, so I don't think this is that big of a deal.