Lingard, whose departure was confirmed earlier this week, gave FC Seoul the lead in the 31st minute but substitute Takeshi Kanamori levelled for the visitors with 16 minutes remaining.
"The most important thing is winning and we drew today," said Lingard. "I felt like we should've won the game, but they could've won the game. It was a game of two halves.
"I'm happy and sad. These two years have been an amazing time for me, I've made friends forever and the fans have been amazing with me. It's very emotional but I'm ready for the next chapter."
The former Manchester United forward put his side in front with a cool first-time finish from 12 yards out following an inch-perfect cross from the right touchline by Choi Jun.
But Kanamori fired a right-foot strike into the bottom corner of the FC Seoul goal in the 74th minute to extend Melbourne City's unbeaten run in the competition to four matches.
The result moves Melbourne City onto 10 points from six matches, one more than FC Seoul with the Australian side in fourth in the 12-team eastern league phase standings.
Japan's Sanfrecce Hiroshima moved up to third, behind compatriots Vissel Kobe and Machida Zelvia who both played on Tuesday, on 11 points after a 1-0 win over Shanghai Shenhua.
Hayato Araki scored the game's only goal in the 78th minute for the home side and the result leaves Shenhua in 11th position on four points.
The first eight finishers in the league phase in both east and west Asia will advance to the last 16 in March with the quarter-finals, semi-finals and final to be played in April in Saudi Arabia.
