Despite an impressive first half for United, a stunning Sam Kerr double in the second half was enough to wrap up the title on the last day of the season that certainly didn't disappoint.
Arsenal had genuine ambitions of pipping the Blues to the title and despite securing a 1-0 victory over West Ham, they couldn't do enough to outdo Emma Hayes' relentless side at Kingsmeadow.
Meanwhile, defeat for Man United meant that they finished the WSL season in fourth position, meaning that arch-rivals Manchester City would secure the third and final Champions League spot following victory over Reading.
It was a nervy start at Kingsmeadow, but United had the first real opening when a corner from Katie Zelem led Alessio Russo's header being cleared off the Chelsea line, before another free kick from the United skipper caused problems.
Those early warning signs sprung alarm bells for Chelsea moments later when another Zelem free-kick found Martha Thomas who converted a header from close range to give Arsenal the advantage in the title battle.
Thankfully for Hayes' side, United's lead lasted just a matter of minutes as Erin Cuthbert slammed home to restore Chelsea's lead at the top of the table.
However midway through the first half, Ella Toone converted from a wonderful cross to make it 2-1 to United.
While Chelsea's falling behind meant it was advantage Arsenal, there's no doubt that the Gunners were starting to get anxious as they spurned a number of excellent chances in the first half against West Ham.
Speaking at half-time on talkSPORT's coverage of the day, Faye Carruthers said: "If anybody can go in at half time and change the mentality of those Chelsea players, it's Emma Hayes.
"We've seen it before, she's going to need a massive team talk today considering what's going on elsewhere."
As it turned out, Carruthers wasn't wrong.
Moving into the second half it took just 47 seconds of the half for Sam Kerr to put themselves back to the top of the table with a stunning volley from the edge of the area that nestled perfectly into the top corner of the net for her 29th goal of the season.
Just four minutes later, Chelsea were 3-2 up when Guro Reiten netted to put them three points clear at the top of the WSL.
Stina Blackstenius was brought on for Arsenal in their clash with West Ham and made an immediate impact after giving the Gunners the lead with her second touch of the match, meaning that the pressure was firmly on Chelsea to retain their lead at Kingsmeadow.
However the Blues need not have worried as the victory was wrapped up with the most spectacular of volleys with her right foot over the top of the goalkeeper and into the top corner of the net to make it 4-2.
Speaking on talkSPORT's commentary, Courtney Sweetman-Kirk described the goal, saying: "That goal is ridiculous and I will tell you why.
"The initial touch on the chest is brilliant to set it up, but to have the audacity to hit it on the volley from there, but also to see out of the corner of your eye that the goalkeeper is off her line.
"She has the audacity to take the look and hit it. What a finish. What a goal. "That's the goal that wins Chelsea the title. The awards she's got this season and importance to this team, she is an unbelievable player."
Stephanie Catley scored a stunner of her own to give Arsenal a 2-0 lead over West Ham, but it was a day that truly belonged to Sam Kerr and Chelsea who showed their class to win their fifth-ever WSL title in the most dramatic fashion.