Dominic Thiem needed a final-set tie-break to reach the semi-finals of the St. Petersburg Open at the expense of Daniil Medvedev and Stan Wawrinka saw off defending champion Damir Dzumhur.
Top seed Thiem, in the hunt for a third title of the year, was pushed all the way by home contender Medvedev but sealed a 6-2 3-6 7-6 (7-2) victory.
The world number eight broke three times and served 10 aces as he set up a last-four encounter with Roberto Bautista Agut.
Thiem said: "I'm very sorry that I beat a Russian guy, but I think it was a great match from the beginning until the end. [A] tie-break in a deciding set is always lucky, so I'm lucky that I won."
Wawrinka showed further signs that he is getting back to something like his best with a 6-3 6-4 defeat of 2017 winner Dzumhur.
The three-time grand slam champion won 71 per cent of points on his first serve and broke three times to advance.
Bautista Agut got the better of third seed Marco Cecchinato 7-6 (7-0) 6-3, while Martin Klizan will face Wawrinka after ousting Denis Shapovalov 3-6 7-5 6-3.
Meanwhile, Kei Nishikori moved a step closer to a first tour-level title since 2016 with a 6-3 4-6 6-4 win over Nikoloz Basilashvili in the quarter-finals of the Moselle Open.
Gilles Simon finally came out on top in an all-French encounter with Richard Gasquet in Metz for the first time, winning 7-6 (7-4) 6-2 to end a run of eight consecutive losses against his compatriot and will take on Radu Albot, who beat Ricardas Berankis.
Matthias Bachinger will be Nishikori's semi-final opponent after he sent fellow German Yannick Maden packing.
|Green: Warriors have to clean up defensively|
|Mariners say Bolt talks ongoing amid reports contract offer was rejected|
|Proud captain Ozil revels in Arsenal´s ´sexy football´|
|Puel angry over Holding handball|
|Cilic breezes through in Basel, Anderson fights back|
|Ingram: Four-game ban better than we expected|
|Raiders send Cooper to Cowboys for first-round pick|
|Arsenal 3 Leicester City 1: Outstanding Ozil inspires comeback win|
|World Series 2018: Three reasons why the Dodgers will win|
|Yarmolenko out for six months after Achilles surgery|
|World Series 2018: Three reasons why the Red Sox will win|
|Ozil eclipses Klinsmann to become Premier League´s most prolific German|
|Allegri expecting Old Trafford battle against Mourinho´s United|
|Bertens feared she did not belong in Kerber clash|
|Returning Ronaldo expecting ´tough´ game against Manchester United|
|Cristiano Ronaldo confident of clearing his name amid rape allegation|
|Osaka looking to learn from losing start in Singapore|
|Kovac expects tough test against AEK Athens|
|Whyte gives Chisora deadline over rematch|
|Spartak Moscow sack Massimo Carrera|
|Atletico Madrid confirm fresh injury issue for Gimenez|
|Dolberg extends Ajax contract after Real Madrid links|
|Ronaldo an example for Lukaku to follow|
|Bertens battles back to blast past Kerber|
|Ramos apologises for training ground fracas|
|Raikkonen should take heed of Alonso misfortune as F1 career winds down|
|Guardiola wants Manchester City fans to push team to Champions League glory|
|Isco not interested in departed Ronaldo - he didn´t want to be here|
|World Series 2018: Three storylines to watch in Red Sox-Dodgers|
|Neymar focus bad for football - PSG´s Maxwell|
|Marco Ianni charged by FA over Jose Mourinho touchline row|
|Stephens sees off Osaka in see-saw Singapore battle|
|I´m happy at Manchester United - Mourinho dismisses Real Madrid reports|
|Semenya and Asher-Smith head IAAF Female World Athlete of the Year shortlist|
|Mandzukic to miss Manchester United trip|
|I turned down Manchester United to return to Juventus - Bonucci|
|Sanchez out of Manchester United´s clash with Juventus|
|Australia make Short work of run chase in T20 win|
|Brotherly g-love! Tommy Fury follows Tyson into the pros|
|Ozil´s international retirement can help Arsenal - Emery|
|If you sack Lopetegui, you have to sack us all – Isco|
|Lopetegui defiant amid Real Madrid sack reports|
|Sri Lanka spinner Herath to retire after Galle Test|
|Ronaldo returns for Old Trafford welcome amid disquieting noise|
|Garcia claims third Andalucia Valderrama Masters title|
|Ex-England international Waldrom retires|
|´Massive personality´ Hart can lift Burnley, says Kompany|
|Liverpool felt wrath of ´emotional´ Klopp, says Shaqiri|
|Reid: Jenkins capitalised on Kaepernick movement|
|Manchester United v Juventus: Ronaldo out to end dismal scoring record against Mourinho|
|Injured Ribery to miss Bayern´s clash with AEK|
|Wilshere would have stayed at Arsenal under Wenger|
|Mahomes stars again as Chiefs crush Bengals|
|Bolt must accept ´much less´ to join Mariners, says A-League chief|
|Klopp compares Liverpool to dog without favourite toy|
|Young leads Hawks to first win, Thunder fall in Westbrook´s return|
|Spalletti hits out at physical Milan – I had three players asking to be replaced|
|Cowboys, Ravens lose after missed kicks in final seconds|
|Hernangomez secures Nuggets´ win over Warriors with last-second block|
|Hasler returns to Manly on three-year deal|
|Sarri: Chelsea fans must respect Mourinho|
|Ronaldo learnt from Scholes – Pjanic praises Juventus star|
|CA dismisses spot-fixing claims|
|WATCH: Will Ferrell leads chants with LAFC fans|
|MLS Review: Galaxy on track for play-offs as Timbers, DC clinch spots|
|Elliott secures win at Hollywood Casino 400|
|Thunder´s Westbrook makes season debut against Kings|
|Saints beat Ravens after Tucker misses extra point|
|Rondo, Paul and Ingram banned after Lakers-Rockets fight|
|Saints QB Brees reaches another historic milestone|