"We suffered tonight, we had to give a lot on Sunday at Burnley and had not recovered completely," he told Sky Sports 1. "But we still came back under difficult circumstances.
"Tottenham played well but we came back, which gives us confidence.
"They had more chances than we had, but when they scored we had a mental blow and struggled to recover from that.
"But for me it's a positive result."
Wenger vowed to resist the temptation to recall his first-choice stars for the return.
"We have made decisions that will stand for the second leg," he added.
"I'm convinced we can do it"