Despite seeing Francis Coquelin sent off and Spurs come from behind to take a 2-1 lead, the Gunners halted a three-match losing streak in all competitions thanks to Alexis Sanchez's equaliser.
It was Sanchez himself who suggested in the build-up to the game that Arsenal did not have the necessary hunger to be champions, but Mertesacker feels differently.
"For a team with low confidence and no belief we played pretty well!" he told reporters.
"As long as we play like that, I am confident. I have great belief in our group and nothing else.
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“We came here with a lot of injuries but never took that as an excuse. That is the biggest statement for ourselves – not for anyone else. We demand a lot more from ourselves and we showed up and everybody noticed that we care.
"We have shown a lot. With 11 men, we played really well and defended well. I have never played in such a demanding game physically."
Arsenal's recent slide, though, means they are now eight points adrift of leaders Leicester City in third place and Mertesacker knows any league hopes are now out of their direct control ahead of their FA Cup fifth-round replay at Hull City on Tuesday.
"It's not down to us anymore so we are not in a position where we can really talk about the title," he said.
"We have shown great character and hopefully that gives us a lot of confidence and a lot of belief for the FA Cup tie and the following league games."