The win aboard the Canadian-owned horse qualifies the Irish rider for the Longines Final 2024 in Riyadh (KSA) in April.
Longines FEI Jumping World Cup
The pair had a big win in Basel in the FEI Jumping World Cup, the late-blooming 17-year-old mare's first indoor Grand Prix victory.
The German rode to victory in the 9th leg of the World Cup Western European League; five more division qualifiers remain before the Final.
The British rider bested a large field of 40 starters aboard a relatively green mount as more experienced pairs had plenty of surprise rails.
The German was astride a relatively new ride, Coolio 42, on an afternoon which saw a surprising elimination for Kevin Staut.
The Canadian and Lehar were edged by her coach Conor Swail riding Count Me In in the $226,000 event; she now sits 3rd in the NA standings.
The Brit stole victory from reigning European champion Steve Guerdat of Switzerland in the eight-horse jump-off in Italy.
The Belgian rider rode Bond Jamesbond de Hay to victory in the third leg of the Longines FEI Jumping World Cup Western European League.
The Irish rider makes it two in a row in Helsinki, winning again just a week after coming out on top at the opening leg in Oslo.
The Irishman, riding Consulent de Prelet Z, beat a star-studded lineup to kick off the Longines FEI Jumping World Cup series in Norway.