Invincible Lee Pyung Kang (2009)

Ji Hyun Woo stars in both dramas and both have historical elements.

It starts out as "enemies" than they end up living together.

Both these dramas are typical Romance Comedies with sports involved. Invincible Lee Pyung Kang is golf based, and Heading to the Ground is Soccer based.

both have the guy that support you behind the scene while hiding his identity and the girl somehow later get to know them because of work related issue

Both dramas star fiesty female leads who are also relatively poor.