The 29-year-old Perth runner comfortably won the sixth and final heat after a half-hour delay in the fifth fastest time. The disruption and conditions seemed to affect the hurdlers as the first round was marked by slow times but Doyle looked solid as she came home in 55.46.
The highlights of the night in the stadium were Kenya’s David Rudisha defending his 800m crown and a surprise gold medal for the host nation in a thrilling men’s pole vault competition as Thiago Braz da Silva stunned the champion Renaud Lavillenie of France.
Following a near full-house to witness Usain Bolt’s 100m victory on Sunday, the crowd in the Olympic Stadium was well down on a wet night, although the Jamaican was back to receive his prize and silver medalist Justin Gatlin was again booed.
However, Da Silva’s thrilling and dramatic upset win for the hosts - only their fourth ever Olympic track and field title - could prove to be just what is needed to spark some much-needed local enthusiasm.
The Brazilian had silver in the bag when he went for 6.03 more in slim hope than expectation of pushing the French star for gold. Da Silva’s previous PB was 5.92 but he soared over for a new Olympic record to spark delirium in the stadium.
Lavillenie had to go higher to win gold but failed to clear at 6.08 and Brazil has its star of the Games.
Eilidh eases through
Eilidh Doyle is hoping she can add to a medal collection that includes European gold and Commonwealth silver and, of the main challengers she is likely to face, Dalilah Muhammad and Ashley Spencer of the United States looked impressive, as did Sara Slott Petersen of Denmark.
Doyle’s old Czech rival Zuzana Hejnova looked to have recovered form after a quiet period.
However, Leah Nugent, one of the Jamiacans who beat Doyle’s Commonwealth conqueror Kaliese Spencer to selection at their national trials, was disqualified for trailing a leg around a barrier.
Sydney McLaughlin, the 17-year-old sensation who denied some big American contenders a place in Rio with her shock performance at the US trials, struggled on her big-stage debut and was lucky to scrape through as a fastest loser after a time of 56.32.
Doyle said: “It was alright. It was a good, solid performance. I was quite nervous, which is unusual for me. I normally get nerves but I felt quite anxious.
“I’ve been in the village watching everybody else and I just wanted to get started. I’m relieved to have got through that round safely and I can go back and relax.
“You’re trying to conserve as much energy as possible but also trying to get your strides in so it’s difficult to run easy. But I’m glad I could just do enough to get through.
“Everybody is just buzzing just now, in particular after Sophie [Hitchon, women’s hammer bronze medallist] got her medal. Everyone is just so happy for her.
“You’re used to seeing someone like Greg [Rutherford], Jess [Ennis-Hill] or Mo [Farah] win theirs but when it’s someone like Sophie, who perhaps wasn’t expected to, you can see how much it means to her and it’s great for the team. Now we’re all hoping we can go out there and perform well too.
“I’d love to run a personal best – this is the place to do it. You want to run your best time when it matters. I feel like I’m in good shape, I’m in personal best shape, so hopefully I can go out there and do something.
“I’m going to have to run [the semi-final] like a final because it’s going to be tough in the semis and hopefully I can get a personal best out of it.”
The semi-finals take place tonight (1.10am Wed UK time), with the final in the early hours of Friday morning.
Earlier, driving rain delayed the start of the evening session. The men’s pole vault final and women’s discus qualifying were halted and, after the first two of five heats, so was the men’s 110 metres hurdles as the track at the Olympic Stadium threatened to turn into a mini flood.
It was announced that the eight athletes who failed to qualify from the first two 110m hurdles heats would get a second chance in another race to be run at 11.15pm local time.
Athletics’ world governing body the IAAF said on Twitter the decision was “taken to ensure fairness”.
David Rudisha retained his Olympic 800 metres title with another imperious display in Rio.
The Kenyan, who broke the world record in taking gold at London 2012, hit the front with 300m to go and stayed strong to come home in one minute 42.15 seconds. It was the fastest time in the world since that unforgettable run in London.
Algeria’s Taoufik Makhloufi took silver in 1min 42.61, with American Clayton Murphy getting bronze.
Rudisha’s 1:40.91 world record from four years ago was achieved with an awesome display of front-running, hailed by Lord Coe as his highlight of the whole Games.
Injuries have prevented the 27-year-old from reaching that level since, but the two-time world champion was still in total control.
His compatriot Alfred Kipketer set a crazy early pace, going through 400m in 49.23 seconds, but Rudisha sped past him down the back straight and from that moment there was only one winner.
It took a head-first dive by Shaunae Miller at the women’s 400m finish line to beat Allyson Felix, denying her a record fifth Olympic gold medal.
Miller, the 22-year-old from the Bahamas, stayed even with Felix for 398m, then sprawled, dove and crashed across the line to edge Felix by .07 seconds.
The rules say the win is determined by which athlete has any part of her torso cross the line first. The photo finish showed the negative image of Miller’s sprawled out body, with her shoulder just barely over the line before Felix reached.
Finally, the result popped up. Miller had won in 49.44 seconds.
Shericka Jackson of Jamaica took the bronze.