Otago captain Craig Newby has branded the Lions cheats after the tourists' 30-19 win in Dunedin on Saturday. The Lions ran in tries from Ryan Jones, Greenwood and Shane Williams, while Charlie Hodgson kicked 15 points.
But Newby said: "I think they cheated... and they got away with it so good on them.
"They really attacked our ball to the letter of the law and got away with that. They slowed it down and turned it over and created penalties."
The Lions had been lucky to go into the interval level at 13-13 when Greenwood scored just before the half-time whistle.
They upped the tempo after the interval for a convincing victory.
Otago coach Wayne Graham was unimpressed by the interpretation of the rules by referee Lyndon Bray.
"I think they were allowed to come in from the side and get the big bodies on the ball," said Graham. "It's hard to play the game at speed.
"I think it's just a deliberate tactic they use to keep the game at their pace. They like playing the game at their speed. It's a game based upon possession, wearing down the opposition and getting into attacking position to score points."
Lions assistant coach Ian McGeechan, however, dismissed any accusations of cheating.
The Scot said: "In New Zealand parlance that means we're now competitive at the breakdown."