Olenna vs. the High Sparrow: In the end, I suppose we have to say that the Sparrow beat Olenna. Maybe not in this exchange, but he is indirectly responsible for wiping out most of her family. Still, “little fellow” is a brilliantly dismissive nickname for the High Septon.
Olenna vs. Tywin: Very few people got the best of Tywin, but Olenna put down the Lannister patriarch a few times when she a) called his prized daughter, Cersei, too old, b) implied that he must have tried messing around with other boys when he was young—come on, not at least once?—and c) brazenly brought up the Lannisters’ dirty little twincest secret.
Tywin matched her move for move, which is why, after he died, Olenna kept telling Cersei how much she admired her late father. She may not have liked him, but these two would have been a formidable ruling pair.
Olenna vs. Cersei: In the end, Olenna’s fiercest opponent proved to be the Queen of Tarts: Cersei Lannister. They traded barbs and, in the end, murdered each other’s children. Woof.
It would be lovely to give Lady Olenna the advantage here, but we have to point out that she was the one who gave Cersei the idea for the wildfire plot in the first place. Taunting the Queen Mother about her unpopularity and pointing out that she was surrounded by enemies on all sides, Olenna wondered if Cersei thought she could take them all out by herself. As it turns out, she did.
Olenna vs. Brienne: But we’ll end this little tribute not on a failure, but on a high note. There is literally only one single, solitary person (other than Margaery) that Olenna ever heaped praise on during her multi-season Game of Thrones tenure. The Queen of Thorns absolutely loved Brienne of Tarth. And that, well, that’s just good taste.