Clue: A bend in the track and son abandons foolish Matterhorn ascent (9,6)
Answer: TATTENHAM CORNER
Explanation: Definition: A bend in the track
***(matterhorn acent)** ( to get anagram fodder, S (son) abandons A(s)CENT) 
*Tattenham Corner is the famous sharp bend of Epsom racecourse, home of the Derby.