The top three all have 45 points from 19 matches and are only separated by goal difference with newcomers Ludogorets, based in Razgrad, a town of less than 35,000 people, aiming for the first league title in their 67-year history.
Anton Karachanakov put CSKA in front with a spectacular curling shot midway through the first half and their Cameroon midfielder Njongo Priso doubled the lead 15 minutes from time.
Captain Ivan Bandalovski then made it 3-0 with a thunderous strike from the edge of the area in the 82nd before Brazilian striker Junior Moraes wrapped up the win with his ninth goal this season after capitalising on a defensive blunder.
CSKA coach Stoycho Mladenov was left hoarse after urging on his players at the Bulgarska Armiya stadium and his assistant Anatoli Nankov replaced him at the post-match news conference.
"I would like to apologise but he [Mladenov] can't speak," Nankov said.
Earlier, Cherno More Varna striker Miroslav Manolov got the fastest goal ever scored in the Bulgarian league after just six seconds with the first of a hat-trick in a 3-1 win at Montana.
Statisticians said the previous record was held by another Cherno More player - Brazilian Marcos da Silva, who scored after 12 seconds against Chernomorets Burgas in 2007.
Ludogorets had slumped to only their second defeat this season on Wednesday, losing 1-0 at Lokomotiv Plovdiv while Levski won 3-0 at Slavia in the oldest Sofia derby.
Champions Litex Lovech, coached by Hristo Stoichkov, were held to a 1-1 draw at lowly Beroe Stara Zagora after five straight victories and are fifth with 38 points, two behind Chernomorets Burgas who won 4-0 at second-bottom Kaliakra.
‘He instantly popped into our ratings as one of the best U21 midfielders in Europe. The impressive thing is Slot has made him into more of a no.6' Inside Ryan Gravenberch's transformation at Liverpool
‘I don’t think Liverpool would look at Ollie Watkins, a striker isn’t a pressing issue for them – it’s Arsenal who need one’ Former Reds star explains why his old club don’t need an out-and-out forward this summer
