Rotterdam - Rotterdam World Tennis boss Richard Krajicek said the entries of weekend title-winners Alexander Zverev and Grigor Dimitrov would soften the box office blow after Rafael Nadal and Stan Wawrinka withdrew due to injury.
The indoor showpiece was left to feature former US Open winner Marin Cilic as top seed, with the 2014 finalist at the Ahoy stadium starting his current campaign against quirky Frenchman Benoit Paire on Tuesday.
The seventh-ranked Cilic aims to escape a run of bad luck which handed him second-round defeats at his last three events in Chennai, the Australian Open and Montpellier.
Krajicek, the 1996 Wimbledon winner, said that the presence of highly-rated German teenager Zverev and Bulgarian Dimitrov, who is 14-1 this season, was a stroke of fortune for his audience.
Both of the young guns claimed titles at the weekend, with Zverev winning in Montpellier over Richard Gasquet while Dimitrov beat Belgian David Goffin at home in Sofia.
"Zverev's here. Dimitrov is here and they both won titles," Krajicek told local media. "There are a lot of good players, highly ranked, in our field. We are all assuming Zverev (now into the top 20) will soon be in the top 10."
Fourth-seeded Czech Tomas Berdych was the only seed on stage for Monday's opening day, with the number four facing Romanian qualifier Marius Copil.
"I'm trying to bring more consistency to my serve and make it more unpredictable," Berdych said in the tournament run-up. "That would be good for me - not for the others.
"I'm also trying to come to the net a bit more," he said as he works under a coaching relationship from last season with 2001 Wimbledon champion Goran Ivanisevic.
In the first round, Frenchman Pierre-Hugues Herbert booked the first of the second-round spots, beating Spanish veteran Feliciano Lopez 7-6 (7/5), 7-6 (7/5).
The tournament also lost Spanish seventh seed Roberto Bautista Agut, who was replaced by lucky loser Denis Istomin, the Uzbek who knocked Novak Djokovic out in the Australian Open second round.