The two Galaxy S7 models have won acclaim for their sleek design and the return from previous models of features such as microSD card storage support and water resistance, though analysts noted the phones offer only incremental upgrades and don't look very different to their predecessors.
Analysts had previously lowered their expectations amid signs of a further slowdown in demand for consumer electronics, and investors took little heed earlier this month when Samsung's new mobile chief Koh Dong-jin said S7 models would outsell previous models following better-than-expected pre-orders.
Samsung's January-March operating profit was expected to fall 16 percent from a year earlier to 5.2 trillion won ($4.51 billion) - the lowest in six quarters - according to a Thomson Reuters StarMine SmartEstimate derived from a survey of 31 analysts.
But the Korea Economic Daily newspaper, citing an unnamed source, said Samsung's quarterly profit will top 6 trillion won on S7 sales and a weaker South Korean won. Samsung said its earnings were not yet finalised, and it declined comment on sales or shipments for the new handsets.
"The majority opinion in the market was that sales would be weak because the S7 is little different from the S6, but that actually helps improve earnings," Mirae Asset analyst Doh Hyun-woo wrote in a report, noting the similarity helped reduce component and development costs.
This helped Samsung launch the S7 models at a lower price than the S6 phones - up to 8.3 percent cheaper in the Korean market - at a time when the S7 had no serious competition other than the iPhone 6S models that were launched late last year.
Investors said the strong start for the S7 suggests Samsung has staying power in the smartphone business, though there's no guarantee of a return to the years of record profits.
"From the investors' perspective, there's nothing wrong with making money without innovation," said Lee Jin-woo at KTB Asset Management.