Forss (85), a former director of Flavour Research at the Invermay Research Centre, started playing tennis as a 15-year-old in Adelaide.
Keys (79), a retired physicist with DSIR and a member of the New Zealand Geophysical Society, was introduced to tennis at age 8 when growing up in Warkworth.
They are both playing in the Carnival doubles at the New Zealand Masters Games.
If they win medals it is a bonus.
Their prime objective is to use the game for recreation and as a social experience to meet old friends.
"I am just playing socially now," Forss told the Otago Daily Times.
"The game is good fun and it keeps me fit."
Forss won a gold medal in the Carnival Doubles with Alister Stuart at the Masters Games in Dunedin two years ago.
He is also a member of the Otago Golf Club and plays three times a week at Balmacewen.
He won a gold medal in golf this week.
Forss is a member of the Cosy Dell Tennis Club in Dunedin.
Tennis was an important recreational game for him when he worked for several years in the United States.
He likes to test his physical limits and ran three marathons and 25 half-marathons after returning to Dunedin.
His best marathon time is 4hr 15min and his best half-marathon was 1hr 40min.
"I have had a hip replacement and can't run much now," he said. "But I still wake up at 4am to go walking for 1hr 30min most days."
Tennis was a game that fitted nicely into Keys' day when he did research work in Germany, and in Samoa and the Cook Islands.
"I love tennis," he said. "It is one of the best social games and you can play it for a whole lifetime."
Keys lives in retirement at Alexandra and finds the Masters Games a special place to catch up with old friends.
He had success in Masters Games tennis a few years ago when he won the championship doubles with former New Zealand football representative Bill Berry.
Forss and Keys showed they had retained their old skills when they played tennis at the Edgar Centre yesterday.
