Joao Sousa's hopes of improving on his 2015 final defeat in the St Petersburg Open this week were ended by Jo-Wilfried Tsonga in the second round on Thursday.
World number 18 Tsonga, seeded second for the ATP 250 event on indoor hard courts at Sibur Arena, won 7-6 (7-1) 3-6 6-2 to defeat the Portuguese, who lost to Milos Raonic in the decider of this tournament two years ago.
Top seed Roberto Bautista Agut needed three sets to advance, the world number 13 eventually pulling clear to see off Brazil's Rogerio Dutra Silva 6-4 4-6 6-0.
Viktor Troicki, the seventh seed, also had to go the distance to get past Guido Pella, the Serbian winning 7-6 (7-3) 4-6 6-4.
Fabio Fognini, runner-up in 2012, registered a 6-4 4-6 6-4 victory to oust the 2004 champion and home hope Mikhail Youzhny.
Ricardas Berankis, using his protected ranking to compete in the event, eased into the last eight thanks to a walkover when Philipp Kohlschreiber withdrew before their match started due to illness, while Jan-Lennard Struff dispatched Thomas Fabbiano in straight sets.