Atletico Madrid boss Diego Simeone says he is learning more than ever this season and expects another examination of his managerial abilities from Arsene Wenger.
The 2-1 aggregate victory put them within touching distance of a third appearance in the competition's final in the space of nine seasons, Simeone having masterminded victory in 2012.
But, amid a campaign where Simeone is "learning most about being a coach", the 47-year-old is braced for a difficult battle with Wenger.
"With their history they are a very strong rival," Simeone said of the Gunners.
"They have a very important coach who is very capable with plenty of experience and quality footballers.
"We know English football and at home they are very strong. It is a 50-50."
Atleti secured a place in the final four despite losing 1-0 at Sporting in the second leg of the quarter-finals.
Highly-rated goalkeeper Jan Oblak, who is reportedly attracting interest from across Europe, produced a couple of key saves to maintain his side's advantage and earned the admiration of his coach.
"Jan is the best goalkeeper in the world and I hope he continues with us," Simeone said.
"He has a contract with us and I hope he remains happy and continues growing as he is today.
"All the teams that end up winning have great goalkeepers. I've never seen a champion team with a bad goalkeeper."