Ireland finished level with Germany on 16 faults after the two-round contest, but were denied by 1.23 seconds after a second-half fightback. The team of Peter Charles (Corrada), O'Connor (Waterford Crystal), Kevin Babington (Carling King) and Dermott Lennon (Liscalgot) were two fences off the lead held by Germany at halfway.
For Babington, the return to Hickstead a year after winning the British Grand Prix proved torrid, Carling King amassing the discard scores in both rounds of 26 and eight.
Faultless performances in the second stage by O'Connor and Lennon, fighting the handicap of a broken bone in his right hand, meant that the Germany anchorman, Ludger Beerbaum, needed a clear or a fast four-faulter to deny Ireland victory. Beerbaum dislodged the first element of the final combination on Gladdys S, but had done enough against the watch to thwart Tommy Wade's men.
The result puts Ireland into sixth, and a qualifying position, in the qualifying league for the final of the Samsung Nations Cup series in Germany next month. It is also a positive step toward the World Championships in Spain in September.
"We were not really tuned up for today and I would be expecting a bigger performance next time," chef d'equipe Wade said.
"Still, at the end of the day, we've done well enough, just pipped," he said.
Wade will announce the squad for the World Championships after the Dublin RDS. Babington's below par performance with Carling King "He just rode a completely different horse," the rider complained presents an opportunity for Jessica Kuerten. But on yesterday's display, it is O'Connor's which will be the first name on the teamsheet.
O'Connor, at 22 the youngest rider in the class, has fought a personal tragedy in recent weeks following the death of his girlfriend, Hazel O'Callaghan, of Rochestown, Co Cork.
Yesterday, the rider from Kill, Co Kildare, filled Waterford Crystal with confidence to record two perfect rounds.
In 11 Nations Cup appearances since May, the pair have recorded five double-clears in seven victories.
"He's a class act, and I'm lucky to have him," O'Connor said.
"Hazel was here last year and won the Young Riders Championship. We'd been talking about coming here and Aachen, and I suppose an Irish boy's dream is to jump on the team in Dublin," he said.
"They're all things that she knew I wanted to do, and she would have been behind me.
"It's no consolation, I know. It was an awful tragedy, and myself and the family will never get over it, but all you can do is try and keep your head up and try and do your best with life."