The Pyga Euro Steel duo beat Scott-Sram MTB-Racing’s Nino Schurter and Lars Forster to the line, with the latter managing to take the yellow jersey.
“For us this is a really special victory after quite a disappointing race so far,” said Beukes.
“We came here with some high expectations for an overall podium, but it just didn’t work out and we went back to the drawing board after day three and decided to take it easy on the time trial.”
Beukes added that they wanted to see if they could win a stage in the last three days.
“It’s amazing that we managed to pull it off on the queen stage, so we’re quite happy.”
Buys said they found the opportunity to be in front with Schurter and Forster early on in the race.
“They made the pace really hard and we sort of rode our own pace to bridge across to them. They had a quick puncture and from there on we worked well together with them.
“It was great to spend the day alongside those guys and it counted for extra motivation. Coming into the urban areas where there was a local crowd also added to our motivation.”
The fifth stage, which covered 100km and 2 850m of climbing, was set to be one of the toughest of the race.
“The almost 3 000m of climbing was definitely a challenging, but even if it was 500m it would also have been hard keeping up with Nino and Lars for four hours. We’re just happy we pulled it off,” said Beukes.
Schurter felt that it was a hard day for them.
“Our plan was to make it hard from the beginning and we were able to put Cannondale Factory Racing under pressure. We got away and Lars suffered a flat so we lost some time, but we managed well and then we had the perfect situation with Pyga.
“They’re racing for the red jersey and we’re racing for the yellow, so it was a pretty cool situation and we just realised we had the same targets.
“They can have the stage and we just tried to pull out as much time as possible for overall. The situation looks quite good now.”
The last time a South African team won a stage was in 2015, which was also Buys and Beukes when they were riding for Scott Factory Racing.