Jose Mourinho's side surrendered first place last weekend when they lost 3-1 at home to Barca in the opening Clasico of the campaign but they go into the Christmas break with a three-point advantage over their great rivals after 16 matches.
Spanish and European champions Barca, chasing a fourth straight La Liga title, have been in action at the Club World Cup in Japan this week and meet Brazilian side Santos in the final on Sunday.
La Liga top scorer Ronaldo, whistled by his own fans and criticised by Spanish media after a poor performance in the Clasico, took his league tally this season to 20 goals, three more than Barca's World Player of the Year Lionel Messi.
Real were cruising with a 3-0 lead at Sevilla's Sanchez Pizjuan stadium after the Portuguese forward struck either side of a Jose Callejon effort before centre back Pepe got a second yellow card when he caught Alvaro Negredo with a flailing arm.
Real captain Iker Casillas had earlier produced two brilliant saves to deny Manu Del Moral and Piotr Trochowski and Del Moral had squandered Sevilla's best effort when he somehow skewed wide in front of an open goal with Real leading 1-0.
Real were forced to defend for long periods at the start of the second half but Sevilla were caught out in the 66th minute when Angel di Maria sped clear and stroked the ball past Javi Varas for the visitors' fourth.
Jesus Navas pulled one back for the hosts in the 69th, Del Moral was shown a straight red five minutes later for hacking down Alvaro Arbeloa and Ronaldo completed his treble with a penalty four minutes from time after a foul on Karim Benzema.
Substitute Hamit Altintop tapped in Real's sixth three minutes later before Sevilla striker Negredo rounded Casillas to make it 6-2 in the second minute of added-time.
MOUTHS SHUT
A combative Ronaldo, who was accused after the Clasico of failing to perform in the big games, said in an interview with Spanish television that his three goals in Seville served to "shut the mouths" of those who had criticised him.
"I don't care what people say I just do my job," added the 26-year-old, who became the world's most expensive player when he joined Real from Manchester United at the end of the 2008/09 season.
"I have shown that I am focused on the team. Those who criticise me don't understand football.
"We played well and are the leaders at Christmas which means our goal has been achieved."
Mourinho praised Di Maria's performance after the Argentina winger flew home in midweek following a death in the family and the Portuguese said he expected a positive reaction from his side after Barca ended Real's 10-match La Liga winning streak.
"Sevilla is always a tough team to play against, a team with ambition," the former Inter Milan and Chelsea manager told a news conference.
"We had a goalkeeper who made two very good saves at critical moments and that has nothing to do with luck."
