The Eagles led by as much as 34 points during the third quarter of Friday's match and the margin was still 28 points at the final change, with Essendon scoring just two goals up until that moment.
But any thoughts of West Coast simply cruising to victory were extinguished as Essendon launched wave after wave of attack in the last quarter to put the Eagles under all sorts of pressure.
In the end, it was Essendon's missed chances that resulted in them falling just short, with the Bombers kicking 2.7 to 0.1 in the final quarter as West Coast clung on for the 6.9 (45) to 4.11 (35) win.
"They really turned it on in that last quarter. They had a lot of territory," Roberts told Fox Footy after the match.
"We couldn't really get it out of their forward half. But we got the four points, and I'm happy with that."
Roberts starred on her special day with 31 disposals, four clearances, one goal assist, nine tackles and 717m gained, while Jaide Britton kicked two goals and Amy Franklin kicked 1.3 and took six marks in a powerful display.
Maddy Prespakis (27 disposals, 466m gained) and Steph Wales (20 disposals, one goal) fought hard for the Bombers, who slumped to a 0-7 record.
West Coast started their season with four losses on the trot, but are now back in the finals mix at 3-4 following three consecutive wins.
Roberts copped several hits during the match, but was able to power on each time.
"I just like the win. I play football to win, and I'm absolutely obsessed with the feeling," Roberts said.
"So if I've got a little stinger here or there, I'm fine to get back up and keep going."
Essendon will be sweating on the fitness of defender Zoe Prowse, who injured her foot in the first half and was ruled out for the rest of the match.
Over at Whitten Oval, the Western Bulldogs improved to 5-2 with a 13-point win over lowly Port Adelaide (2-5).
Bulldogs forward Heidi Woodley was the star in the 10.2 (62) to 8.1 (49) win, kicking a career-high four goals from 18 disposals.
Ellie Hampson kicked three goals to go along with a goal assist in her Port debut, while Shineah Goody chipped in with two majors and Matilda Scholz had a huge day in the ruck with 22 disposals, 40 hitouts and five clearances.
But the Bulldogs' deadly accurate return of 7.0 in the second half meant Port were never able to claw back the 13-point half-time deficit.
Carlton moved to 5-2 and gave their percentage a handy boost with a 55-point win over Richmond (4-3) at Ikon Park.
Erone Fitzpatrick kicked three goals for the Blues in the 11.10 (76) to 3.3 (21) win, while Abbie McKay was big with 27 disposals, five clearances and a goal.Â
