Ciara Mageean set another Irish 1500m record as she clocked 3:55.87 to take second behind Laura Muir at the Brussels Diamond League meeting.
After trailing Muir by two metres at the bell, Mageean moved on to the Scot's shoulder with 200m left only for the European champion to kick again.
Muir took victory in 3:55.87 as she followed last week's Zurich 800m win.
Mageean was among seven of this year's World Championship 1500m finalists in action in the Belgian capital.
However, Kenyan star Faith Kipyegon and other medallists Ethiopia's Diribe Welteji and Dutch star Sifan Hassan were not in the Brussels field which left Mageean, who took fourth in Budapest, as favourite to repeat her triumph at the meeting 12 months ago.
While the main contenders were some way behind the pacemakers over the first two laps, Muir's burst just before the bell gave her a two-metre advantage over the pack and while Mageean looked poised to move ahead around the final bend, the Scot maintained her form brilliantly to reverse last year's Brussels placings.
Mageean's time cut 0.74 seconds off her national record set at last month's World Championships.
The county Down woman produced her first sub four-minute 1500m when triumphing in Brussels 12 months ago as she held off the Commonwealth and European champion to clinch a breakthrough Diamond League victory in 3:56.63.
Kenya's Nelly Chepchirchir, fifth in last month's world final, took third in 3:56.93 as the top nine all went under four minutes - including British duo Katie Snowden (3:58.03) and Melissa Courtney-Bryant (3:58.09) who finished fifth and seventh respectively.
After winning in Brussels last year, Mageean went on to finish second in the 1500m at the Diamond League Final and the conclusion to this summer's series takes place in Eugene in the United States next weekend.
Following her season of upheaval after a well-publicised change of coach, Muir is finishing the summer on a strong note following her sixth place at the World Championships.