This is from Sagat's wikia:
Street Fighter Alpha
In the retconned events of
Street Fighter Alpha, Sagat enters the tournament to exact his revenge on Ryu, and succeeds. Although pleased that he got his revenge, he somewhat felt empty after the fight. Sagat realized that Ryu didn't give it his all, and he believes Ryu held back. Sagat eventually gave up this vendetta, considering it to be foolish and pointless.
Street Fighter Alpha 2
He then immediately set about tracking Ryu down. He soon caught up to his rival and challenged him to a fight, with Ryu protesting that Sagat had not fully recovered from their last one. Sagat persisted, and won. Afterwards,
he couldn't help but feel that the victory was hollow somehow, and realized that Ryu had let him win; after the match, Ryu had not said a word, and merely gave him a mysterious look.