Every fantasy football fan knows, running backs are key to a successful season.Week 1 is the most magical time of the year. Everybody's roster looks like a championship winner, and now comes the big decisions. Which of your running backs should you send out to beat your first victim on the road to glory?Read on as we look at who to start, who to sit, and rank the top 10 running backs set to play a major role in Week 1.Start 'EmJoe Mixon ready to go crazy 🐅 pic.twitter.com/ryXAlOaC9H— PFF Fantasy Football (@PFF_Fantasy) September 10, 2021#1 - Joe Mixon, Cincinnati Bengals, vs Minnesota VikingsExpect the Cincinnati Bengals training camp MVP to be an even bigger part of Joe Burrow's passing game following running back Giovani Bernard's departure. The Vikings defense allowed the sixth-most rushing yards per game last season, and they are once again without key linebacker Anthony Barr.#2 - Najee Harris, Pittsburgh Steelers, at Buffalo BillsNajee Harris was drafted from Alabama to boost the Pittsburgh Steelers' offense and, with backup Anthony McFarland injured, the first-round rookie running back is set for a major role on his NFL debut. Bills nose tackle Starlite Lotulelei has been ruled out and Pittsburgh will work their ground attack hard as quarterback Ben Roethlisberger transitions further into a game-manager role.#3 - James Robinson, Jacksonville Jaguars, at Houston TexansIt's unlikely first overall draft pick Trevor Lawrence will be thrown into the deep end on his NFL debut and James Robinson will be the man charged with taking the pressure off the rookie quarterback. The Houston Texans were the worst team in the league at defending the run in 2020 and could be set to be even worse this season.Sit 'EmTE T.J. Hockenson (shoulder) and RB D’Andre Swift (groin) both off the pregame injury report. https://t.co/iRmFaUcU2F— Stephania Bell (@Stephania_ESPN) September 10, 2021#1 - D'Andre Swift, Detroit Lions, vs San FranciscoD'Andre Swift has been cleared to play in Week 1 but could still be struggling with a groin injury. The second-year running back missed the whole of the Detroit Lions' training camp and preseason with the issue. Head coach Dan Campbell could quickly abandon the run game if the 49ers go up early. San Francisco's run defense was the seventh-best in the NFL in 2020.#2 - Antonio Gibson, Washington Football Team, vs Los Angeles ChargersMany are tipping Antonio Gibson for great things in 2021, but hold off the second-year rusher in Week 1. Fellow running backs J.D. McKissic and Jaret Patterson could be set for sizeable roles in Scott Turner's offense. Washington quarterback Ryan Fitzpatrick may need to throw the ball early and often to keep up with second-year QB Justin Herbert's high-tempo Chargers offense.#3 - Chris Carson, Seattle Seahawks, at Indianapolis ColtsChris Carson practiced through the week after coming off a neck injury, but caution is advised as the Seattle Seahawks rusher lines up to play against the NFL's second-best run defense in 2020. Fellow running backs Rashaad Penny and Travis Homer could both get looks in head coach Pete Carroll's ground attack.Top 10 fantasy running back starts in Week 1Christian McCaffrey, Carolina Panthers, vs New York JetsDerrick Henry, Tennessee Titans, vs Arizona CardinalsDalvin Cook, Minnesota Vikings, at Cincinnati BengalsAlvin Kamara, New Orleans Saints, vs Green Bay PackersAaron Jones, Green Bay Packers, a New Orleans SaintsJoe Mixon, Cincinnati Bengals, vs Minnesota VikingsNick Chubb, Cleveland Browns, at Kansas City ChiefsSaquon Barkley, New York Giants, vs Denver BroncosNajee Harris, Pittsburgh Steelers, at Buffalo BillsJames Robinson, Jacksonville Jaguars, at Houston Texans