Portugal, Italy and Poland were the only three countries that applied to host the games in June 2019, reason why Portugal won the first place and will now lead the heyday of the inaugural competition.
Portugal secured their place in the League of Nations finals after a 0-0 draw in Italy secured first place in Group A3.
Italy can not take chances, with Ciro Immobile wasting their best opening in the first half.
The draw at San Siro means Portugal, who host Poland on Tuesday, can not be overtaken at the top of the group and will play host to the finals next summer.
All three countries that applied to host the June final were in Group A3, so Portugal's victory will leave them as the only candidate to attend the event, subject to a formal meeting at a meeting of the Uefa executive committee on 3 December.
Santos: Portugal deserved a draw
Portugal's boss Fernando Santos felt that his team deserved the point in Italy, which earned him the qualification for the League of Nations finals.
Santos's team ran out of Cristiano Ronaldo again but they did the job at San Siro to finish the top of Group A3 ahead of Italy and relegated to Poland.
"It's a fair result because, from a moment in the second half, Portugal was better," Santos told a news conference after his team struggled to contain Italy before the break.
"In the first, with the moves in the midfield, Italy managed to win many second balls.
"The internal movements of (Lorenzo) Insigne created a lot of problems. (João) Cancelo did not always close the game well and that made Ruben Neves very low, leaving Pizzi and William (Carvalho) in situations of two against three.
"We realized what was happening and we improved, the suffocation was over, the game was balanced, we were growing and we were able to withdraw, we were forced to play behind the ball and we were improving."
League of Nations Round
Scotland will win Group C1 if they defeat Israel on Tuesday after a 4-0 win over 10-man Albania in Tirana.
Steven Fletcher scored on his international comeback when Alex McLeish's team went to the top of the group.
The Sheffield Wednesday striker has not played for his country for more than a year, but scored a penalty in the first half to put the visitors ahead 2-0.
Bournemouth's Ryan Fraser scored his first goal for the international squad after setting the scoring in the 14th minute before Mergim Mavraj was sent off for the hosts.
James Forrest's double in the second half gives Scotland the platform to beat the group on Tuesday and seal a place in the play-off.
Sweden kept hopes of promotion to the top flight of the League of Nations with a 1-0 win in Turkey, which was relegated to League C.
Andreas Granqvist's penalty in the second half was enough to lead Sweden to four points in Group B2.
Janne Andersson's team are expected to beat Russia – who lead the group with seven points – on Tuesday to reach League A.
Serbia defeated Montengro 2-1, leading Group C4, although Aleksandar Mitrovic missed a penalty.
The Fulham striker scored Serbia's second after Adem Ljajic opened the scoring, but missed the scoring when he did 7 minutes before half-time.
Stefan Mugosa pulled a goal back with 20 minutes remaining.
Kosovo beat Malta 5-0 and Azerbaijan beat the Faroe Islands 2-0. The teams mark a confrontation between the winner and the winner when they face on Tuesday in Group D3. Elsewhere, Romania beat Lithuania 3-0 in Group C4.