[2] Diehl played at the 2005 World Championships in Anaheim, United States.

In the women's singles event she reached the second round before losing to Salakjit Ponsana of Thailand.

In October 2005, Diehl won the women's doubles event at the Scottish International Open in Glasgow, and two weeks later followed this up by winning the women's singles event at the Irish International in Lisburn.

In 2010, Diehl won the bronze medal at the European Individual Championships in Manchester,[2] and in June 2010, claimed the European Tour circuit finals title, beating Susan Egelstaff in the final in three sets.

2010 also saw Diehl beat current world champion Lu Lan of China to reach the semi-final of Swiss Open.