With the one-off Ashes Tests, which form part of the multi-format series, the only guaranteed games in the format Australia get - although this is their second of the season after the game against India in October - and most nations not playing them, Haynes admitted it might be the final time she pulls on the whites for her country.
Her 86 was the third occasion she had got within touching distance of a Test century following her 98 on debut in Worcester in 2009 and the 87 in Taunton two years ago. Having taken advantage of being dropped on 44, she was closing in on triple figures until receiving a terrific delivery from Katherine Brunt which bounced to take the glove.
"It's probably a fair assumption, think it probably will be my last Ashes Test," she said. "I just want to enjoy it. It's a really special occasion, not just for me but for the whole team. This series is one that's held in really high regard. First and foremost I just want to focus on tomorrow and get another good day's play."
Haynes combined in a 169-run stand with captain Meg Lanning - who was dropped on 0 and 16 - which lifted Australia from 43 for 3, and things had been even more uncertain when Haynes watched from the non-striker's end as Alyssa Healy and Beth Mooney edged to the wicketkeeper inside the first four overs.
As much as the missed landmark, it was the fact Haynes' departure came just three balls after Lanning had also fallen narrowly short of a century that frustrated her, although the partnership between Ashleigh Gardner and Tahlia McGrath ensured Australia ended on top despite McGrath falling to the last ball of the day.
"I wasn't thinking about it [the hundred] to be honest," she said. "I was more just disappointed to lose two wickets in a row. It just opened the door a little bit but think our batting order rallied really well and had a good counterpunch. It was pretty good to watch as well, the contest between Ash and Katherine [Brunt], it was good fun. It was a really positive way to finish the day."
If the chance had been taken off Lanning before she had scored, edging low to second slip, Australia would have been 43 for 4 and if she had been held by Heather Knight at slip in the last over before lunch it would have been 78 for 4.
However, Nat Sciver said that overall England were satisfied with seven wickets on the opening day having opted to bowl in conditions where she felt runs could be scored at a good rate throughout the game. Four wickets in the final session kept them in the hunt after Australia had scored 120 without loss between lunch and tea.
"All the bowlers can do is create them [the chances]. We have to take them really," Sciver said. "We're frustrated with the drops and maybe we lacked a bit of energy in the middle session.
"We brought it back at the end and feel pretty positive…probably buoyed a little more with the wicket on the last ball. When they got in it seemed a lot easier to score so hopefully that's what we can do."