Why do you say Olenna is the best player of the Game? From all evidence it seems as though Petyr is able to manipulate her easily.
It certainly didn't seem like Olenna has been manipulated by Petyr at all and i think she is probably the only person who realises how gifted Lord Baelish is at the Game. I would say that she is a better player solely based on the ongoing fortunes and eminence of House Tyrell. As we know, the least scathed House in Westeros - with almost all of their forces intact. Olenna is certainly Mace's string puller. She it was who suggested Margeary for Renly. She it was who then agreed with Petyr over Margeary for Joffrey/Tommen. She probably had significant input in getting Loras Kingsguarded.
I see the collusion between Petyr and Olenna as a coming together of near equals (particularly the seamless transition of the power of the Reach going from supporting Renly to the Lannatheons/Bannisters (i love that wordplay btw)).
Olenna represents the power that a woman has to control and manipulate all the men and events around her - regardless of age or beauty - it all comes back to brains. She has them, uses them, and then uses the cover of being a tottering old woman with her immense bodyguards at beck and call.
Petyr is similar. he shows the potential of even the most minor lords to rise to positions of staggering power. opportunism, brilliance, brutal practicality. However, he has a few blind-spots and his rise has not gone unnoticed. He has yet to make the mistake of declaring against the Iron Throne, but it would be foolish to think that events in the Vale have gone unnoticed at King's Landing.
Olenna is known for her cunning, but is dismissed due to age and gender, Petyr minor lord he was or not, can no longer be dismissed. Too fast a rise... a catastrophic fall ahead? or the Iron Throne itself perhaps.
He certainly doesn't seem like a leader worth mentioning though. He'd be capable, but good i don't know. He's rather jackal like, and as soon as his "followers" particularly those in the Vale of Arryn loyal to House Arryn and not the Regent, see an opening, another jackal will rip his throat out. Sansa perhaps... though she may be better termed a dire wolf... the Stark side in her seems to be coming out... tempered by a greater knowledge of the Game than perhaps even Ned had.