In 1985 under Ron Atkinson, United beat Aston Villa 4-0 with goals from Mark Hughes(2), Norman Whiteside and Jesper Olsen. Eventually ended the season in 4th place after such a promising start when they remained unbeaten till November.
In 2003 under Sir Alex Ferguson, United beat Bolton Wanderers 4-0 with goals from Ryan Giggs(2), Paul Scholes, Ruud van Nistelrooy. Finished the season in 3rd place.
In 2006 and still under Sir Alex Ferguson, United beat Fulham 5-1 with goals from Louis Saha, Wayne Rooney(2), Cristiano Ronaldo and an Own Goal. Finished the season as Champions.
In 2017 under Jose Mourinho, United beat West Ham 4-0 with goals from Romelu Lukaku(2), Anthony Martial, Paul Pogba. Finished 2nd which Mourinho considered his greatest achievement.
All of the above huge opening days victories were achieved at Old Trafford. In sports records are meant to be broken but here is hoping for a great season from MUFC.
Chelsea opening day fixtures:
MUFC did beat Chelsea 5-2 in 1958 where Sir Bobby Charlton scored a hat trick and Alex Dawson got two more. Finished runners up famously by drawing upon their indomitable spirit post Munich disaster.
In 1952, United beat them 2-0 with goals from the two Johnny's Berry and Downie.
In 1953, United drew with them 1-1 with goal from Stan Pearson.