[20] On 23 February 2020, Tilio scored on his A-League debut, to secure a 3–1 win over Central Coast Mariners and send his side 13 points clear at the top of the table.

[21] On 7 September, after making 6 appearances and scoring 1 goal, Tilio departed Sydney FC to find better playing time, rejecting the contract offer made by Steve Corica.

[25][26] Following Adrián Luna's suspension and Andrew Nabbout's absence from injury, Tilio made his Melbourne City debut on 3 January 2021, in a starting appearance against Adelaide United.

[28][29] On 17 April, after being brought off the bench in the 63rd minute in his first Melbourne Derby, Tilio recorded two assists and won a penalty that helped Jamie Maclaren complete his sixth hat-trick in his league career.

[38] In the A-League semi-final on 20 June, Tilio assisted the opening goal, a cross towards Stefan Colakovski, and scored a brace within a minute later to secure a 2–0 victory over Macarthur.

[42] At the end of the season, Tilio was award the club's Rising Star accolade,[43] and was nominated among four other A-League players, including teammate and eventual winner Connor Metcalfe for the Harry Kewell Medal.

[46][47] Despite being replaced by Florin Berenguer in recent matches, Tilio kept his place in the starting line-up before the Christmas break following a 2–2 Melbourne Derby draw on 18 December where he got an assist.

[48] On 5 January 2022, in the FFA Cup quarter-final, Melbourne City were knocked out from the competition after losing on penalties following a 0–0 draw against Wellington Phoenix at the end of extra time.

[51] Following his return from international duty, on 18 February, Tilio assisted twice, to both Mathew Leckie and Carl Jenkinson, in a 3–0 win against Newcastle, sending his side to the top of the ladder.

[54][55] Following the match, the Football Australia (FA) referee department admitted that referee Shaun Evans got it wrong in the two controversial decisions that cost the Central Coast Mariners, and said that City's penalty should not have been awarded due to the secondary contact in the area being "negligible" as well a penalty that should have been awarded to the Mariners in the 87th minute due to a foul on Lewis Miller that was not given.

[72][73][74] This repeated in the next round against Brisbane Roar as Tilio was instead brought on at stoppage time due to Taras Gomulka red card leading to a change in tactics.

"[75][76] With only 20 minutes in the domestic league, Tilio's chances of making it to the World Cup squad for Australia was described by reporters and pundits as "hanging by a thread" although Leckie ensured him to concentrate and work hard.

[83][84] He repeated this performance on 25 February, during a league match against Sydney FC, Tilio dribbled from his team's half of the pitch to score a goal from outside the box, increasing the lead to 2–0.

[85] As March came to a close, Tilio's goal tally reached 5, along with numerous assists, solidifying his belief that he was ready for European football as he announced his intention to depart Melbourne by the end of the season.

[87] In the final round on 28 April, Tilio scored twice again, including the winning goal in the 93rd minute, to help City make a 3–2 comeback against Western Sydney Wanderers,[88] leading his side to their third consecutive Premiership Plate – becoming the first club to ever do so.

[102] At age 17, Tilio played his first international game against the Vietnam U-20s in the 2019 AFF U-18 Youth Championship group stage where he scored a hat trick in the 1st, 34th and 90th minute.