Root scored a magnificent hundred as England thrashed West Indies by eight wickets at the Ageas Bowl in Southampton on Friday.
Root was pushed up the order to open after Jason Roy sustained a hamstring injury, and he responded with an unbeaten century to help England chase down 213 runs with more than 16 overs to spare.
The Test skipper struck 11 fours and faced only 94 balls as England registered their third win of the ongoing tournament, thus fuelling their hopes of winning the World Cup for the first time.
The 28-year-old became only the second England batsman to hit two tons in a single World Cup after Kevin Pietersen, who smashed two centuries in the 2007 edition. Root notched up his first century against Pakistan on June 3, but his team lost that game.
"Joe had a good day out. He is such an important part of our team. He is the glue that holds the team together and is an awesome player to watch," Morgan said after the match.
Morgan was forced to leave the field after suffering a back spasm and could be a doubt for England's next game against Afghanistan on Tuesday.
"It is my back. It is a bit sore at the moment and hopefully it settles down in the next few days," said Morgan. "I have had a lot of back spasms in the past. It is a matter of 24-48 hours before it settles down, sometimes it gets healed a lot quicker and sometimes it lingers around."
Roy also limped off, giving England another headache. "He had a tight hamstring so he will go for a scan tomorrow and probably it will take 48 hours before we have the results," the England skipper said on Roy.
Meanwhile, Root seemed pleased after getting his second ton of the tournament. "It is obviously nice to get the ton... You pride yourself on as a batter for converting those starts into hundreds," said Root who was adjudged the Player of the Match.