Impey, of Mitchelton-Scott, and Gibbons, of Dimension Data, lost out in a sprint finish to Lotto Soudal’s Caleb Ewan and Deceuninck-QuickStep’s Elia Viviani.
KordaMentha Real Estate’s Nathan Elliott and Astana’s Laurens De Vreese took on the Challambra climb alone just more than 60km into the race, eventually creating a two-and-a-half minute lead over the peloton.
Over the top of Challambra Elliott began to tire after his efforts and De Vreese opened up a slight gap on the descent.
Davide Ballerini and Dimension Data’s Nicholas Dlamini rode clear of the bunch on the same descent.
The two caught De Vreese just before the third climb in Challambra, before Ballerini broke clear on the ascent.
Ballerini went into the final 16.6km lap with a minute’s lead over the peloton.
Nothing materialised from the escapees, as the sprinters within the the peloton launched their attacks in the final eight kilometres.
View more results below.
1. Elia Viviani (Ita) Deceuninck-QuickStep 3:54:35
2. Caleb Ewan (Aus) Lotto Soudal
3. Daryl Impey (RSA) Mitchelton-Scott
4. Ryan Gibbons (RSA) Dimension Data
5. Jens Debusschere (Bel) Katusha-Alpecin
6. Luke Rowe (GBr) Team Sky
7. Michael Mørkøv (Den) Deceuninck-QuickStep
8. Jay McCarthy (Aus) Bora-Hansgrohe
9. Owain Doull (GBr) Team Sky
10. Luis León Sanchez (Spa) Astana Pro Team
11. Benoit Cosnefroy (Fra) AG2R La Mondiale
12. Robert Gesink (Ned) Team Jumbo-Visma
13. Diego Ulissi (Ita) UAE Team Emirates
14. Kenny Elissonde (Fra) Team Sky
15. Ruben Guerreiro (Por) Katusha-Alpecin
16. Chris Hamilton (Aus) Team Sunweb
17. Wout Poels (Ned) Team Sky
18. Sven Erik Bystrøm (Nor) UAE Team Emirates
19. Alberto Bettiol (Ita) EF Education First Pro Cycling
20. Nico Denz (Ger) AG2R La Mondiale