"During the regency of Aegon III in 133 AC, Ser Willis Fell, the Lord Commander of the Kingsguard, died of the Winter Fever alongside two of his sworn brothers of the Kingsguard. In their stead, King Aegon III Targaryen appointed Ser Robin Massey as Lord Commander and Ser Robert Darklyn to the white cloaks. With the support of Grand Maester Munkun, Lord Unwin Peake, the Hand of the King, dismissed all the appointments and arrangements of the twelve-year-old king, who had not consulted with his regents. His Kingsguard appointments were reversed, with Ser Marston Waters being elevated to Lord Commander while Lord Peake's bastard half-brother, Ser Mervyn Flowers, and nephew, Ser Amaury, were made knights of the Kingsguard.
In 135 AC Amaury and a dozen men-at-arms were ordered to seize Maegor's Holdfast by Ser Marston, the newly-named King's Hand, to arrest Lady Larra of Lys when the Rogare family were accused of plotting to overthrow Aegon. However, Larra's husband, Prince Viserys Targaryen, and the king refused to give her up. Viserys planted a battleaxe upon the drawbridge and warned Amaury and his men not to cross it, before retreating back into the castle. Amaury ordered his men to take the boys gently and to see no harm come to them. Larra's guard, a former pit fighter named Sandoq the Shadow, emerged to face Amaury and his men. As Sandoq dueled Amaury, he wounded the Kingsguard and then slew another guard. Amaury rushed Sandoq after the pit fighter was disarmed of his sword, but Sandoq used Viserys's battleaxe to split the knight's head and helm in half. Amaury's corpse toppled onto the spikes below the drawbridge of the keep."
This is the history of the wiki for the Kingsguard Sandoq beat
Amaury wasnt even chosen firstly by Aegon to be a kingsguard it was only because of the hand of the king that dissmissed all of Aegon III choices that Amaury (hand of the king nephew...) was choosen. So don't know how strong that lad was. Likley nothing huge lol.
And it was said that during the fight Sandoq at one point was disarmed. So not a walk in the park either for him.
Still a very good feat for Sandoq for beating 12 guys in a row
But beating Maelys the Mounstrous in a clean 1 vs 1 is a better feat