A century from Lauren Winfield-Hill had ensured Diamonds posted a formidable total of 279 all out which looked to be enough until first Jones and then Glenn carried Sparks over the line with eight wickets down and ten balls to spare.
Earlier, Winfield-Hill had reached three figures off 123 balls, but her efforts were in vain as Sparks went on to snatch a scarcely credible victory.
Diamonds’ innings saw Issy Wong pick up an impressive 5-49 from her 10 overs, but only Glenn could offer any meaningful support as a scrappy performance in the field saw Sparks drop catches and concede 22 extras, including 18 wides.
Wong and Emily Arlott had kept things tight early on with the teenage quick picking up the early wicket of Hollie Armitage, bowled with a vicious yorker for 13, before Natalie Sciver hit one straight to Eve Jones at midwicket for seven, to leave Diamonds 38-2.
From then on it was all about Winfield-Hill as she began to feast on Sparks’ supporting bowlers and together with Sterre Kalis constructed a third-wicket partnership of 112.
When Kalis was out lbw to the impressive Glenn, Katherine Brunt took over and the England legend was there to witness Winfield-Hill bring up her century with a towering six into the Western Terrace off Ria Fackrell. Winfield-Hill eventually fell in the 42nd over to a good catch from Fackrell off Steph Butler but Brunt’s 46 and useful cameos from Jenny Gunn, Alex MacDonald and Beth Langston ensured Diamonds’ total was more than adequate.
Sparks got off to the worst possible start, losing both their opening batters without scoring as Brunt and Langston picked up a wicket each.
But Jones and Marie Kelly sparked a recovery as they compiled a partnership of 103 for the third wicket before Kelly holed out to Brunt off Linsey Smith for 31 with the same bowler then forcing Milly Home to edge behind for one.
A stunning one-handed catch from Gunn accounted for Butler for three but Jones stood firm and brought her own century up from 106 balls with three sixes and 11 fours.
When Jones was caught by Amy Campbell for 114 the writing was on the wall for Sparks but Glenn had other ideas as she smashed a quick-fire 50 from 38 balls as an unbeaten ninth wicket partnership of 87 with Arlott saw the Sparks home.
Winfield-Hill said: “It’s a bittersweet feeling. It’s nice to get my first ton at Headingley but it feels like we played 80 overs well and 20 overs poorly.
“It was difficult early on but I have worked hard on getting through those tough patches in one day cricket and make some big scores.
“I thought we had a really good score on the board at half-time and we were confident but we just didn’t back it up at the end and I think if we are being brutally honest we were complacent mixed with a lack of experience of being in that situation.”
Attention now turns to today’s fixture against Lightning at Kibworth Cricket Club in Leicestershire (10.30am).
Diamonds’ former England all-rounder Jenny Gunn said: “You can lose and learn quickly, but nothing beats winning. I’m desperate for us to go one better than last year when we reached the final.”
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