With only a single point separating the two sides at the back end of last season, the Emirates Stadium welcomed Emma Hayes' Chelsea side who looked to extend their lead on their closest competitors.
Sam Kerr continued her great form, rescuing Chelsea from a goal down with a perfectly-timed header to deny the Gunners of a vital three points.
It was Kim Little with the opener, a collected penalty from the spot by the 32-year-old after Caitlin Foord was brought down at the edge of the box by Niamh Charles.
Arsenal did see more of the ball and attacking chances but were pegged back with one minute of normal time remaining, which means they still trail the Blues in the league table by three points as we enter the second half of the WSL campaign.
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Story of the match
The Gunners got off to the better start, Erin Cuthbert handing Stina Blackstenius possession too easily, who gave Zekira Musovic her first test of the afternoon.
Jonas Eidevall's side were warned early by the attacking prowess of Lauren James, slaloming past two Arsenal defenders on the right wing. The 21-year-old then cut inside, her curling effort just wide of the top-left corner.
Caitlin Foord & Lina Hurtig both had opportunities to test Musovic, but the Swedish keeper stood firm, catching both efforts with ease.
The closest chance of the first half came around 30 minutes in, Hurtig's powerful shot smashing the side netting after an intelligent ball from an in-form Frida Maanum.
However, the Blues did grow back into the game towards the interval, with a string of corners coming to no real avail.
The Gunners started the second half as they did 45 minutes earlier, dominating possession and working it well into the Chelsea box.
Lina Hurtig should've easily opened the scoring after she wisely escaped her marker, but her header was tame and parried by Musovic.
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A controversial penalty breaks the deadlock for the Gunners
It only took a few more minutes for Arsenal to open the scoring. Niamh Charles caught Caitlin Foord drifting inside the box and referee Emily Heaslip immediately pointed to the spot.
Although replays showed that the foul didn't occur in the box, the experienced Kim Little stepped up to the plate, waited for Heaslip's whistle, and placed the penalty calmly to the right. Around 45,000 fans erupted inside the Emirates Stadium as the deadlock was broken.
The Blues were starting to crumble. Maanum located Foord in the box, but luckily for Chelsea, the Australian international mistimed her volley and it was cleared away.
Hayes recognised the game was slipping away and opted to bring on Eve Perisset and Fran Kirby in a double substitution for Niamh Charles and Jessie Fleming.
Foord then had another chance, this time her low-drilled effort into the bottom right parried away by Musovic.
Welsh international Sophie Ingle had a chance on the edge of the box for the Blues, her strike flashing past a helpless Zinsberger, luckily for the Arsenal number one it was just wide of ricochetting into the top corner.
With 20 minutes to go, Steph Catley almost registered herself as a contender for goal of the season. The cross from distance searching for Blackstenius left its effect on the crossbar.
Chelsea captain Magdalena Eriksson could've drawn the visitors all square, but her header off a routine free kick was caught safely by Zinsberger.
With ten minutes to go, the Blues started to pile the pressure even more on the Gunners. Johenna Kaneryd was brought on in an attempt to provide more attacking options.
Perisset finding the side netting was a sign of things to come for a persistent Chelsea side who kept fighting. But who else but Sam Kerr was there to rescue Chelsea again. A world-class cross from deep by Jelena Cankovic found the Australian, who leapt into the air and placed it well past Zinsberger into the back of the net. The 29-year-old wheeled away to celebrate in front of the Arsenal fans, saving two points that could've easily been dropped on another day.
It was the second largest attendance of WSL history, an outstanding 46,811 fans at the Emirates that were treated to the late dramatics which means that Chelsea have solidified their top spot ahead of the race to the title. They sit three points ahead of the Gunners and will face Liverpool next week in their quest for another WSL title.
Jonas Eidevall's side will have to keep mounting the pressure on the Blues, their next opposition is Brighton next Sunday at Broadfield Stadium.
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Player of the match
Kim Little - Arsenal
The 32-year-old is still crucial as ever for the Gunners, scoring her first goal of the season with a collected penalty in front of a packed Emirates Stadium.
With Jordan Nobbs departing to Aston Villa,, her pairing with Lia Walti in the midfield will be crucial for Arsenal as they focus on dethroning Chelsea come May.