Rafael Nadal helped hosts Spain see off Argentina in a deciding doubles contest, setting up a semi-final against Great Britain.
Serbia had hoped to mark Janko Tipsarevic's farewell by winning the Davis Cup, but Russia ruined those plans in Madrid on Friday.
There was another encouraging performance from Andy Murray in Antwerp as he saw the back of eighth seed Pablo Cuevas in straight sets.
Lorenzo Sonego was no match for Jo-Wilfried Tsonga in Antwerp, while Janko Tipsarevic made an announcement over his future in Stockholm.
Roger Federer says he is feeling no pressure in Paris after outclassing Lorenzo Sonego in his first Roland Garros match for four years.
A two-time runner-up in Houston, Sam Querrey reached the semi-finals thanks to a hard-fought victory against Janko Tipsarevic.
Seeking a Houston three-peat, top seed Steve Johnson fell to a shock 6-3 6-3 defeat to Colombian qualifier Daniel Elahi Galan on Thursday.
Wildcard Janko Tipsarevic caused a first-round upset against 2018 runner-up Tennys Sandgren at the US Men’s Clay Court Championships.
Janko Tipsarevic saw off world number 93 Bradley Klahn in straight sets on Wednesday for his first tour-level victory since August 2017.