Denis O'Sullivan and Miguel Angel Martin both hit three-under-par 67s to take joint lead of the Wales Senior Open after the first round.
English trio Graeme Bell, Paul Wesselingh and Malcolm Mackenzie are two shots further back on one under.
Home favourites Ian Woosnam and Mark Mouland are part of an eight-strong group on par at Celtic Manor Resort.
"My back was really hurting and the pace of play is so slow I couldn't keep my rhythm going at all," Woosnam said.
"When I'm moving I'm fine, but when it's five hours five minutes [to play a round]... how can you play golf? It's not on."