On the final straight it was Trek-Segafredo on the front, with Koen de Kort leading John Degenkolb out, but Groenewegen hit the front to lead the sprint out.
The Dutch champion went for a long one on the right-hand side of the road, with Mark Cavendish – who had been boxed in – fighting to get on his wheel.
The Manxman had no space to pass the Dutchman, however, whereas Kittel had picked the left-hand side of the road – correctly as it proved.
With open road before him, the German dropped the hammer with perfect timing to claim victory for the second consecutive stage and extend his blue jersey lead.
Dubai Tour 2017: stage two – report
1) Marcel Kittel (GER) – QuickStep Floors – 4.25.33hrs
2) Dylan Groenewegen (NED) – LottoNL-Jumbo – ST
3) Jakub Mareczko (ITA) – Wilier Triestina
4) John Degenkolb (GER) – Trek-Segafredo
5) Sacha Modolo (ITA) – UAE Abu Dhabi
6) Juan Jose Lobato (ESP) – LottoNL-Jumbo
7) Mark Cavendish (GBR) – Dimension Data
8) Riccardo Minali (ITA) – Astana
9) Marco Maronese (ITA) – Bardiani-CSF
10) Adam Blythe (GBR) – Aqua Blue Sport
General classification
1) Marcel Kittel (GER) – QuickStep Floors – 8.31.46hrs
2) Dylan Groenewegen (NED) – LottoNL-Jumbo +8”
3) Nicola Boem (ITA) – Bardiani-CSF +13”
4) Jempy Drucker (LUX) – BMC Racing +14”
5) Tom Stewart (GBR) – ONE Pro Cycling – ST
6) Mark Cavendish (GBR) – Dimension Data +16”
7) Jakub Mareczko (ITA) – Wilier Triestina – ST
8) Yousef Mirza (UAE) – UAE Abu Dhabi
9) Silvan Dillier (SUI) – BMC Racing
10) Pete Williams (GBR) – ONE Pro Cycling +19”