Matteo Berrettini upset sixth seed Leonardo Mayer in the first round of the Swedish Open on Monday.
Italian Berrettini, up to a career-best 75th in the rankings after a shock win over Jack Sock in the first round at Wimbledon, came from a set down to win 3-6 6-3 6-4 on the opening day in Bastad.
Mayer was beaten by Jan-Lennard Struff in the first round of Wimbledon and made an another early exit back on clay after being broken three times.
Norweigan teenager Casper Ruud came out on top in a Next Gen battle with Jaume Munar, winning 6-7 (7-9) 6-4 6-0.
The 19-year-old could face three-time champion David Ferrer in round two, having saved six of seven break points to oust the Spaniard.
Guido Pella made it through to round two in the Croatia Open Umag, getting past Taro Daniel 1-6 6-3 6-3.
Laslo Djere won the only other first-round match, seeing off Pablo Cuevas 6-4 1-6 6-3.
