"This was a first important signal that Italy cannot go on alone supporting this huge weight," Salvini said at a news conference after Spain agreed to take in the ship.
That tense episode shed light on how Italy's new populist, anti-immigration government could influence the years-long debate in Europe over which countries should take in migrants and how their asylum claims should be handled.
According to European rules, refugees applying for asylum must do so in the country where they are first registered - a situation that does not suit frontline countries such as Italy and Greece, where many migrants first land.
Today, as part of a regional effort to deal with migrants, the European Commission offered to pay countries up to US$7000 ($10,000) per migrant they take in, hoping to persuade more countries to accept migrants rather than simply turn them away.
Brussels also offered to pay for the hundreds of staff members needed to manage centres where migrants and asylum seekers could be processed to avoid having them travel through Europe to secondary destinations.
Italy quickly rebuffed the suggestion.
"We aren't asking for charity handouts. Every asylum-seeker costs the Italian taxpayer between 40,000 and 50,000 euros," Salvini said after the offer was announced. "Brussels, they can keep their charity for themselves."
The commission's latest suggestion that it pay countries to deal with migrants' arrivals follows an all-night summit in June, which led to an agreement that the European Union would help establish centres to process asylum claims. Some of those centres could potentially be in Africa. EU diplomats are expected to more formally discuss the offer this week, even if Salvini has already dismissed it.
Jeff Rathke, a senior fellow at the Centre for Strategic and International Studies' Europe program, said that "it's not really about the money for the Italians."
"It's about their desire along with a few other like-minded EU member states to shift the debate and shift the paradigm of how Europe is dealing with migration," Rathke said. "I think it's unlikely that a particular level of compensation is going to change the approach or perspective of this Italian Government."
Salvini, for his part, made that much clear today.
"We don't want money," he told reporters. "We want dignity."