Solskjaer surprisingly left Ronaldo on the bench for the first 57 minutes of Saturday’s damaging 1-1 draw at Old Trafford.
United were leading 1-0 when the Portugal star was introduced, but Andros Townsend equalised to leave Solskjaer’s misfiring team with only one win in their past four games in all competitions.
Ronaldo has been in fine form since rejoining United, scoring five times in his first six games, including the late winner against Villarreal three days before the Everton match.
In a conversation with former UFC champion Khabib Nurmagomedov in the directors’ lounge at Old Trafford, United legend Ferguson was filmed saying “you should always start with your best players”.
In the video, posted on Nurmagomedov’s Instagram account on Sunday, Ferguson suggested Everton got a boost “when they saw Ronaldo wasn’t playing”.
Ferguson played a key role in Ronaldo’s blockbuster return to United in August, making a phone call to his former player to convince him to snub an offer from Manchester City in favour of an emotional move to Old Trafford.
The Ronaldo deal, combined with the high-profile signings of England forward Jadon Sancho and France defender Raphaël Varane, have raised expectations of a United title challenge this term.
Solskjaer, who played under Ferguson from 1996 to 2007, is still waiting to win his first trophy since taking over in December 2018.
United finished second in the Premier League last season and lost the Europa League final against Villarreal on penalties.
They last won the Premier League in Ferguson’s final season in charge in 2013 and have not won any silverware since 2017.