Simmonds's medal hunt underway
The 19-year-old from Beverley touched the line three hundredths of a second ahead of Spofforth to retain her 100m backstroke title at the British Gas Swimming Championships in Sheffield last night.
The victory also ensures Simmonds, who is a two-time world finalist and 200m Olympic finalist, a place in the European Championships in Budapest in August.
Simmonds stopped the clock at 59.43 seconds and said: "To swim a personal best, which is up there with the best in the world, is fantastic and it's one of my best moments.
"We've had great support from everybody here in Sheffield, and it's a very exciting competition for me to race in.
"I now look forward to the 200m on Friday night."
That event will see Simmonds and Spofforth, 22, continue a rivalry that is elevating both to new heights.
Simmonds was a finalist in both the 200m and 100m backstroke at the World Championships in Rome last year, finishing seventh in the latter as Spofforth claimed the title and lowered the world record, albeit in a now-outlawed polyurethane suit.
Simmonds overturned that deficit in front of a healthy crowd of 500 at Ponds Forge last night and heads into the two major meets this year confident the pair can challenge for the top step of the podium.
"Being in the lane next to the world record holder is really enjoyable," said Simmonds.
"She had a fantastic year last year and it was always going to be a close race.
"Hopefully we'll go to the Europeans and Commonwealths this year and win some medals for the team."
Their relationship echoes the friendly rivalry between Northallerton's Jo Jackson and double Olympic freestyle champion Rebecca Adlington.
Jackson was an Olympic bronze medallist in Beijing behind Adlington, and turned the tables in Rome last year by winning three medals, two of them ahead of Adlington in the individual freestyle events.
But the 23-year-old has been struck down this winter by asthma, brought on by flu and a chest infection, which forces her to breathe much harder in the pool and has resulted in her ribs regularly popping out.
The pain is intense for days afterwards meaning there is little respite for Jackson, which underlines the willpower that guided her to a third-place finish behind Adlington in the 200m freestyle on Monday night which qualified her for the relay in Budapest.
Jackson, who broke the world record in the 400m at this meet last year, is waiting to hear whether the Yorkshire Primary Care Trust will allow her to be prescribed Xolair, a treatment that can cost up to 8,000 a year and is only usually available for those who have a history of emergency hospital treatment.
She has withdrawn from the 800m freestyle – the final of which is tonight with Adlington the hot favourite – but the pair will go head to head again tomorrow in the 400m.
Jackson is yet to qualify for the individual races in 2010's major championships and Adlington said: "It's a bad situation but Jo will qualify for the big events at the second trials. The 400 is her main event and it makes sense for her to concentrate on that."
City of Sheffield's Rebecca Turner matched her seventh-place finish in the 200m freestyle in last night's 100m final, in a time of 56.62.
Turner's Sheffield team-mate Max Partridge finished sixth in the men's 100m breaststroke.