The Gunners demonstrated their new-found resilience to fight back from a goal down to earn a deserved 1-1 draw against Liverpool.
But for a glaring miss in front of an open goal by substitute Nicklas Bendtner after Cesc Fabregas' 80th-minute equaliser, Arsene Wenger's emerging squad would have extended their winning run to 13 straight matches.
Gallas maintains the Gunners have what it takes to stay in the battle over the next seven months.
"We showed everybody we can fight for the title," he declared. "A lot of people wanted to see how Arsenal would react against a big team like Liverpool and we reacted very well. Maybe we can be disappointed because we didn't win."
"Liverpool were maybe a little bit afraid of us and a lot of top teams will be afraid of us again.
"We play well, we can score at any time or we can play the physical game as well."
Arsenal moved back to the top of the table yesterday, above United on goals scored but with a match still in hand.
Liverpool, though, slipped back down to sixth following a fourth home league draw.
Gallas, 30, knows there are plenty more challenges ahead if Arsenal are to finish top of the pile come May.
"For me, it will be very difficult to win the title," the centre-back reflected.
"There are three or four teams who can win it.