 It was also the second non-album single penned by the band and also reached number 6 in South Africa.Once "In Rock" had been completed, EMI asked for a suitable single to be recorded to help promote the album.Though Roger Glover states that Ricky Nelson's 1962 hard rocking arrangement of the George Gershwin song "Summertime" was the basis for the Mk II Deep Purple single "Black Night", it is also similar to Blues Magoos's 1966 psychedelic hit song "(We Ain't Got) Nothin' Yet".