"There are a lot of quality teams here, but I think we have had a ideal score so far with winning all the sets and hopefully we can keep going".
Djokovic, meanwhile, criticised the situation that emerged on Tuesday night when Canada were allowed to forfeit their doubles rubber against the US having already won both singles matches.
The 16-time major champion beat Paire 6-3, 6-3 after Filip Krajinovic won a close encounter 7-5, 7-6 (7/5) against Jo-Wilfried Tsonga to give Serbia a 2-0 advantage, making France's doubles victory irrelevant.
Two separate line calls went against Serbia and left the pair infuriated, while Djokovic also called out the trainer due to issues with his elbow before his team pulled through to take it 6-4 and force a decider.
Instead, the three-time grand slam champion was cheering from the side as Kyle Edmund played brilliantly to see off Mikhail Kukushkin 6-3, 6-3 before Dan Evans was beaten 5-7, 6-4, 6-1 by Alexander Bublik to leave the tie in the balance. "We came here not knowing what to expect. I think everyone should be obliged to come out and play".
"I just think moving forward that is the way the sport has to go".
I understand that Canada is through already, they won both of their ties. and they wanted to rest their players for the quarter-finals and onwards.
Serbia eased through on Thursday, following up victory over Japan with a 2-1 success against France that eliminated the top seeds.
Djokovic had a break in the first set and two in the second to clinch his 14th straight Davis Cup singles victory.
For the second day in a row, captain Leon Smith did not play Murray who, after a comeback victory in the first tie of the group stage, said he was not in his best shape.
After guiding Serbia into the quarter-finals, Novak Djokovic said: "I think it was always going to happen, knowing that you have 18 teams and you're trying to squeeze everything in in one week on three courts".
Russian Federation were one of the two best-placed runners-up along with Argentina, who will take on hosts Spain.
It made the gamble to leave Murray out of the singles all the more bold, even if the Scot appears to be struggling for fitness after his lengthy duel with Holland's Tallon Griekspoor on Wednesday.
In Group C, Germany was leading Chile 1-0 after Phillip Kohlschreiber defeated Nicolas Jarry 6-4, 6-3. I'm really disappointed with myself. In addition, the time between the first and second singles matches will be reduced from 20 minutes to 10 minutes, and the doubles match has to start within 30 minutes of the second singles.
Djokovic suggested only having eight teams in the finals week - something that organisers would resist given the concept of the "World Cup of Tennis" - while Jamie Murray offered the idea of playing the event across two venues.