Fourth seed Mardy Fish survived a scare to beat teenager Ryan Harrison 6-4 3-6 7-5 at the Japan Open on Monday in a titanic struggle between the present and future of American tennis.
Top seed and defending champion Rafa Nadal and Britain's Andy Murray lead a strong field at the $1.34 million tournament on Tokyo Bay but neither were involved on the opening day.
After splitting the first two sets, former Olympic silver medallist Fish fought off three break points at 3-2 down in the decider against 19-year-old qualifier Harrison.
Fish's extra experience told at crunch time, a thumping forehand sealing victory in a match which began in sunshine and finished under floodlights lasting two hours and 44 minutes.
Spaniard Nadal kicks off his defence against Japanese wildcard Go Soeda on Tuesday.
Seventh seed Radek Stepanek of the Czech Republic beat India's Somdev Devvarman 6-4 6-3 while Australian qualifier Matthew Ebden beat Spain's Pablo Andujar 6-7 6-4 6-4.
Murray will be given an extra rest day before he faces Marcos Baghdatis of Cyprus after the Briton won the Thailand Open in Bangkok at the weekend.