Blues won only one of their five games in the tournament held in Lithuania.
“Results didn’t go quite as well as we would liked, but you could not fault the girls for effort,” he said.
“They battled so hard that most of them came away with niggling injuries.”
The most serious of them was Emma Thomas, who strained a calf muscle early in the second of their three Pool A games.
“We were certainly in the toughest of the two groups,” added van Willigen.
Blues made a promising start to their opening game on Friday against Den Bosch, taking a second-minute lead through Wiz Hunt.
Blues stayed ahead until the first minute of the second half, but the Dutch champions added three more goals to win 4-1.
In their second game, they lost 4-2 to MSC Sumchanka, who were virtually the Ukrainian national team.
Reading trailed 3-0 at half-time before hitting back in the second half through Emma Thomas and Emily Maguire.
The third game, however, proved a disaster. They crashed 8-1 to Hamburg after being 4-0 down at half-time with Maguire getting their consolation goal.
Despite being without the injured Thomas, Reading bounced back to hammer French side Cambrai 6-1. They led 4-1 at half-time following strikes from Ellie Cockburn, Ashlie Caddick, Hunt and Maguire.
Maguire and Cockburn added to the tally in the second half.
In the next stage, Reading lost 3-2 to host club Gintra Strekte University after being one-up at half-time thanks to Susie Gilbert.
She scored again to make it 2-1, but the Lithuanians equalised on 30 minutes with a penalty stroke.
Reading withdrew keeper Sarah Ellis to play with five outfield players and went close to snatching victory before conceding a third goal in the last minute.
Van Willigen described that loss as “gut wrenching”, as his girls had produced an “amazing team effort.”
Reading’s final placing of seventh means that England’s next European representatives, Bowdon Hightown, will be relegated to the Trophy competition in 2016, along with France’s champions.
Final placings: 1 Hamburg, 2 Club De Campo De Madrid, 3 Sumchanka, 4 Slavia Praha, 5 Den Bosch, 6 Gintra Strekte, 7 Reading, 8 Cambrai.
Reading squad: Sarah Ellis, Abi Harper, Emma Thomas, Wiz Hunt, Ashlie Caddick, Ellie Cockburn, Susie Gilbert, Emily Maguire.
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