O'Brien, Natasha Thomas and Sophie Peskett got the goals as Town Women beat Plymouth Argyle 3-1 at Portman Road in front of 10,807 fans.
Speaking after the game, she said: "It was so special. I didn't think we could top last year but we've done it.
"We've got a new record crowd and another three points.
Lucy O'Brien scores an early goal for Town to give them a 1-0 lead.Lucy O'Brien scores an early goal for Town to give them a 1-0 lead. (Image: Steve Waller)
"It's very rewarding seeing so many fans turn up to watch us play, it was such an honour, almost as special as the three points.
"Portman Road is a carpet so we were able to play some really good football and connect between the lines which we love to do. It was a good performance."
O'Brien scored the first goal of the game, firing in from a spilled shot into an empty net.
"I said to the girls, I don't think I could have missed it, but it was special all the same", she said.
"It was so emotional for me, at the end of the game I did get a bit tearful because it means so much.
Lucy O'Brien celebrating after scoring an early goal for Town to give them 1-0 lead.Lucy O'Brien celebrating after scoring an early goal for Town to give them 1-0 lead. (Image: Steve Waller)
"Not just the match, not just the three points, but inspiring the next generation - it's such an honour.
"Hearing the noise of the crowd after I scored will stay with me.
"I think when we walked out the tunnel as well, when you first hear that roar, it gives me goosebumps.
"To score a goal after two minutes and hear the crowd erupt it was a special feeling and something I will cherish for a long time."
At the end of the game, the club put out a video on social media of Suffolk pop superstar Ed Sheeran, who was in attendance, singing along with the players in the dressing room.
Lucy O'Brien celebrating after scoring an early goal for Town to give them a 1-0 lead.Lucy O'Brien celebrating after scoring an early goal for Town to give them a 1-0 lead. (Image: Steve Waller)
"That was so special" she enthused.
"He's such a famous and well-known person, but he's really down to earth, such a nice guy.
"It was a special experience for all of us.
"I am honoured to have been able to share that moment with him and I wonder if he knows my name now after scoring in front of him."
This win takes Town top of the Women's National League Southern Premier Division on goal difference, with two games in hand over Hashtag United who lost to Gwalia United today.
O'Brien scored Town's first of the gameO'Brien scored Town's first of the game (Image: Steve Waller)
O'Brien said: "We won't look at the table too much. We'll work hard every week.
"We will go to training on Tuesday and we'll put in the work.
"Work hard, graft away and will see what happens come the end of the season but it is exciting."
Following the players' rendition of Castle on the Hill with Sheeran, the squad returned from the tunnel to sign autographs and take pictures with a vast number of people who had waited behind for them.
O'Brien said: "It's great for the whole team.
A number of fans stayed behind to meet the playersA number of fans stayed behind to meet the players (Image: Steve Waller)
"Fans want everybody's autograph, everyone's picture and it is so special.
"I think to be a role model for the younger generation and inspire them, it's a magical feeling and I'm honoured to be part of this team.
"The club has backed us and we are so lucky to be part of this club.
"The backing helps the women's game grow and it does inspire the younger generation."
Town's next game is against Gwalia United back at the Martello Ground in Felixstowe on Sunday, March 30.