A small close-knit community has been rocked by the tragic death of a teenager killed on her way to watch her brother play football.

Emily Critchley, 17, was travelling along Rowney Road west of Mundulla in South Australia's south-east when she lost control and hit a tree just after 8.30am on Saturday.

The Bordertown teen was the sole occupant in the car and was on her way to Kingston to watch her brother play football.

Her brother and one of her friends travelling in another car behind her were among those who witnessed the horrific single car crash.

'I heard this bang and had a look out in front and seen the car,' friend Riley Colls told Seven News.

'She was always caring. A person who was there for everyone.'

Emily worked at the Bordertown Hotel, which paid tribute to the teen on Facebook late Sunday night.

'Saturday morning we lost one of our own when Em Critchley was killed in an accident on her way to footy,' the post states.

'Em joined our pub family only five months ago but had such a huge impact that we thought she had been with us for way longer than that. She was bossy, sassy, fun, beautiful (inside and out), entertaining and most of all a much loved member of our team. Our sincere condolences to her parents and siblings. Forever in our hearts.'