premise: The 2015 City of Onkaparinga ATP Challenger was a professional tennis tournament played on hard courts. It was the first edition of the tournament which was part of the 2015 ATP Challenger Tour. It took place in Happy Valley, Australia between 3–11 January 2015.
hypothesis: The 2015 City of Onkaparinga Challenger took place on courts made from concrete.
reason: Concrete is a hard surface but not necessarily something made into a tennis court.