Arsene Wenger's side were the main beneficiaries of last weekend's wobbles by leaders Chelsea and fellow challengers Manchester United and Manchester City in a season that is becoming more unpredictable by the week.
Sitting two points behind Chelsea on 26, Arsenal could leapfrog them if they beat Spurs before Carlo Ancelotti's team's later kick-off at Birmingham City but may end up just keeping the seat warm for the champions.
Arsenal have already thumped their arch rivals 4-1 this season in the third round of the League Cup and have lost just once in the league to them in 11 years - April's 2-1 defeat.
Ex-Arsenal skipper Gallas, who crossed the north London divide in August, has yet to win over some Spurs fans but gets the perfect opportunity to do just that at the Emirates, where he spent four years from 2006.
Adding to defender Gallas's valuable insider knowledge, Spurs also have a dangerous attacking weapon ready to use earlier than expected in Jermain Defoe.
The England forward resumed training this week after suffering an ankle injury on international duty in early September that was expected to sideline him for three months.
If he fails to make it Peter Crouch is on hand and will hope to continue his scoring run having netted in Spurs' 4-2 win over Blackburn Rovers last week and England's 2-1 defeat to France on Wednesday.
Another England striker who could be back in action this weekend is Manchester United's Wayne Rooney, who has returned from a week of intensive training in the United States after an ankle injury that has dogged him for much of the season.
He will be assessed on Thursday to see if he is ready to return to action.
Third-placed United, who trail Chelsea by three points, host Wigan Athletic on Saturday and after dropping more points against Aston Villa last weekend could be looking to take out their frustration on a team they beat 5-0 twice last season.
Team-mates hope Rooney, who has been in the media spotlight more than he has been on the pitch this season because of revelations about his private life and the saga surrounding his new contract, will be back to his best once he returns.
"A fit Rooney is one of the best players in the world," said defender Rio Ferdinand. "He has gone away and worked really hard physically. We all hope he comes back in great shape and ready to play for Manchester United and England in the future."
The table is so tight in the middle that five points separate 17th-placed Wigan and fifth-placed Bolton Wanderers.
Chelsea will be looking to make amends for last Sunday's shock 3-0 drubbing by Sunderland at Stamford Bridge when they travel to Birmingham, who pulled off one of the other surprises of last weekend when they held Manchester City 0-0 at Eastlands.
Manchester City have not scored in their last two games and manager Roberto Mancini will start to really feel the heat under his
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