It is not that the defending champions have suffered European "hangovers" this season - they have picked up seven points in the league after their three Champions League games.
"I can't explain it to them, though, it was just an awesome season".
But Ranieri said he wanted to keep him fresh as the Foxes juggle their Champions League and Premier League campaigns.
Okazaki played an understated but important role in last season's Premier League title triumph, and his fame had spread when he returned home in the summer.
Leicester have now gone 20 league games at home without defeat and, while nobody expects them to win the league again, this performance should kill off any premature talk of a potential relegation battle.
Leicester are also on the brink of qualifying for the Champions League knockout rounds after three group stage wins, and Ranieri wants to build a team that will be a threat in Europe.
Victory extended Leicester's unbeaten home record in the Premier League to 20 games, and Ranieri, who celebrated his birthday on Thursday, said: "I think it's the best performance of the season.
Ahmed Musa is slowly getting better and starting to understand the Premier League too".
Palace were the stronger side early on, and came closest when Christian Benteke thumped a header against the crossbar.
Last season Leicester won both fixtures against Crystal Palace 1-0.
Leicester manager Claudio Ranieri: "I feel good".
CRYSTAL PALACE (4-4-2): Mandanda 5; Kelly 6 (Fryers 77), Delaney 6, Tomkins 6, Ward 6; Ledley 7 (Lee 72), Cabaye 7, McArthur 7, Townsend 6 (Campbell 72); ZAHA 8, Benteke 8. "Leicester are now a very big team in Japan and I'm proud of that".
Claudio Ranieri's side were on course for their first win in four league matches after Nigeria global Musa claimed his first Leicester goal in his 10th appearance since a pre-season move from CSKA Moscow.
Okazaki scored the second goal himself before Christian Fuchs landed a beauty from 25 yards and Yohan Cabaye clinched deserved consolation for the visitors.
Leicester's next match will be at White Hart Lane against Tottenham on 29 October.
After that wasted opportunity Palace began to set the tempo of the match.