But it doesn't stop there, Biggar kicking a touchline conversion to win a top-of-the-table clash at Leinster on March 23, capping a 13-point comeback and ending Leinster's 20-game unbeaten run in the process.
In the national side, Warren Gatland opted for Rhys Priestland at fly-half in Wales' Grand Slam winning campaign, although the Scarlets' form came under scrutiny.
And with Biggar's kicking game leading Ospreys to second in the RaboDirect PRO12 standings, Tandy thinks it is about time he returned to the international scene.
"Obviously he's a great option for Warren this summer," Tandy said.
"Bigs have been exceptional for us the last fortnight. He's been great in and around training for a long time - he won us a lot of games at the start of the season with his goal-kicking as well.
"In fairness to Biggs in the last two games he's really stepped it up - he's really constructive with everything he's doing, he's running our game for us.
"We've put ourselves in a good position with the last two results to get that home semi, but first and foremost we've got to get in the play-offs. We nail that and we're looking for a good three performances to finish the season.
"You've just got to look at the team Cardiff have got, the internationals they've got in there, they're still capable of putting a performance in."
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