Quins, hosts to second-placed Saracens at Twickenham next Tuesday, have dropped just seven points from a possible 50 in winning all 10 of their league games so far.
Saracens are nine points adrift, with third-placed Exeter a further nine points behind - but then just five points separate the Chiefs and Wasps, currently ninth.
Northampton, despite their Heineken Cup exit effectively being confirmed just two thirds of the way through the pool stage, will go into Christmas holding third spot if they beat Franklin's Gardens visitors Bath on Saturday.
Then on Boxing Day, Wasps visit Gloucester and Sale Sharks entertain Newcastle, with Tuesday's action - outside of the Quins versus Saracens showdown - taking Exeter to London Irish and Leicester visiting Worcester.
Leicester, for instance, were languishing in the Premiership's lower reaches early last month, but they have now climbed to seventh, and victories over holiday opponents Worcester and Sale could put them in the top four.
"We've got some big games over the Christmas period, and if we can win them we put ourselves in a very good position in the Premiership table going into the second half of the season," Tigers rugby director Richard Cockerill said.
"It's very tight in the league, and if we lose one or two in this spell then we are in that mid-table group with everybody else and it becomes tough.
"There is a short turnaround after Worcester for the Sale game at home on New Year's Day, then six days for Wasps, then we go to Ulster in the Heineken Cup. That is a big spell in the season."
Northampton and Bath will meet each other on the back of contrasting Heineken Cup results last weekend, when Saints crushed Castres 45-0 a day after Bath shipped 50 points to European champions Leinster in Dublin.
"These games come thick and fast. There is no respite," Bath assistant coach Martin Haag said. "We can't focus on the past too much. We need to move on.
"Things are constantly being assessed and looked at. The majority of things stay the same because we really trust what we are doing.
"There is constant communication with players to make sure they are happy with what we are doing, and if not, there is discussion. It's a constant process of review."
Quins, meanwhile, have lost the services of flanker Will Skinner for their next two league fixtures against Saracens and Exeter after he was handed a fortnight's suspension.
Skinner received a red card from Irish referee Alain Rolland for what European Rugby Cup described as "an act contrary to good sportsmanship" during Quins' Heineken Cup victory over Toulouse in France five days ago.
It followed an incident a minute from time at Le Stadium when Skinner, who had been replaced some 30 minutes earlier, played the match ball in the technical zone and prevented Toulouse from taking a quick lineout throw.
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