Maikel Franco hit a three-run homer in a six-run fourth inning Sunday in Philadelphia's season-ending 11-0 rout.
"A great day for the Phillies, a great day for me," said Mackanin, who found out this week that he would not return as manager after 2 1/2 seasons. "It was really special, probably one of the best days of my career."
Collins, at 68 the oldest manager in the major leagues, is stepping down after seven seasons that marked the longest tenure in Mets history.
Expected to contend for an NL East title, the Mets were beset by injuries and went 70-92. It was a 17-game drop-off from last year and their worst season since finishing with the same mark in 2009.
"We certainly had bigger plans," Collins said.
Collins and Mackanin exchanged a hug along with lineups before the game. Mackanin was greeted by his entire roster standing outside the railing of the first base dugout and was given a standing ovation from the crowd of 25,754.
"I almost started crying," Mackanin said. "I didn't want to cry. It was really special. It meant a lot to me. I don't know who set it up. I looked at (bench coach Larry) Bowa and I said is this for me? He said yeah, tip your cap. I didn't know what to do."
Philadelphia announced Friday that Mackanin will not return as manager. He finished 174-238, and will become the senior adviser to general manager Matt Klentak.
"I think he deserved" the ovation, said shortstop Freddy Galvis, who became the first Phillies player to play all 162 games since Ryan Howard in 2008. "He was a good manager. He was a good person. He's a good person. He treats everybody with respect and that's pretty cool."
The Phillies finished last in the NL East at 66-96, five more losses than last year. Philadelphia went 37-38 after the All-Star Game when the club started to call up some of their prized prospects, including first baseman Rhys Hoskins, outfielder Nick Williams and J.P. Crawford.
"The time that I was up here, I think we played some pretty exciting baseball," Hoskins said. "At times, we either pitched and didn't hit or hit and didn't pitch, that's baseball. But I think it's pretty special when we did both, and I think that's pretty apparent."
Hoskins hit .259 with 18 home runs and 48 RBI in 50 games and 170 at-bats.
Franco's homer was his 24th of the season and fourth in five games. A disappointing season saw him benched in September in place of converted shortstop Crawford.
Williams hit a three-run, inside-the-park home run in the eighth.
Nick Pivetta (8-10) allowed two hits in five innings, and three relievers were hitless.
New York starter Noah Syndergaard threw 26 pitches in two hitless innings, his second appearance since returning from a partial tear of his right lat muscle.
"I felt like today was the best I ever in my entire life," Syndergaard said. "I felt like I owed all my success to (pitching coach) Dan (Warthen). It really helped me out a lot. I was able to clean up my delivery a little bit. Today was the best I ever felt in terms of pitching ever and I'm excited by the way that I finished up the season."
More AP baseball: https://apnews.com/tag/MLBbaseball
With demand down, Boston might be Craig Kimbrel's best bet
In the same way the Red Sox held out for J.D. Martinez in a crowded market, they could do the same for their free-agent closer.
The state of the starting pitching market
A look at who is still available in free agency, who could be involved in a trade, and the teams that could use a rotation upgrade.
Wilson Ramos, Mets reportedly agree to two-year contract
The Mets have their catcher, agreeing to a two-year deal with Wilson Ramos, per multiple reports.
Bradley promotes 2019 London Series
Red Sox outfielder Jackie Bradley Jr. weighs in on the 2019 London Series in which the Red Sox will take on the Yankees in London on June 29-30.
Top spenders Red Sox owe nearly $12 million in luxury tax
The World Series champion Boston Red Sox owe $11.95 million in luxury tax for having baseball's top payroll.
White Sox, James McCann reach 1-year deal
James McCann, who hit .220 with eight homers and 39 RBIs in 118 games for the Tigers last season, will stay in the AL Central after reaching a one-year deal with the White Sox.