Over the following months he tried unsuccessfully to qualify for the main draw of the Gerry Weber Open in Halle, the Mercedes-Benz Cup in Los Angeles, and the Canada Masters in Toronto.

He spent the bulk of the 2003 season playing on the Challenger Tour and reached the semi-final stage of events in Fergana and, after coming through qualifying, Nottingham, where he lost to second seed John Van Lottum.

[7] He won another Futures title in January in Doha and the following month reached his first Challenger final in Belgrade – along the way defeating a teenage Novak Djokovic in one of his earliest professional appearances.

[7] He won his first main draw match on the ATP Tour at the 2004 Gerry Weber Open, overcoming compatriot Michel Kratochvil in straight sets, but lost in the next round to Jiří Novák.

In September he took his first Challenger title in Donetsk and came through qualifying at the 2004 AIG Japan Open in Tokyo in October, eventually reaching the round of 16 after upset victories over the higher ranked Alexander Peya and Dennis van Scheppingen.

[9] He soon received his first call up to the Switzerland Davis Cup team for the tie versus the Netherlands, losing in five sets to the more established Sjeng Schalken, and later winning the dead rubber against Peter Wessels.

After retiring through injury in his second round match against Michael Ryderstedt at Wimbledon Qualifying in June, Chiudinelli was later forced to get surgery to heal persistent pain in his shoulder.

After coming through qualifying at the Gerry Weber Open, Chiudinelli defeated Christophe Rochus in the main draw, before falling to the seeded Kristof Vliegen in the second round – the ranking points from this event moving him back up to 359.

[8] Following the US Open, Chiudinelli won the dead rubber against Serbia's Janko Tipsarević at the 2006 Davis Cup World Group play-offs and made the semi-final of the Mons Challenger in October.

He also played the longest doubles match ever with Stanislas Wawrinka, being defeated by Lukáš Rosol and Tomáš Berdych of the Czech Republic in the first round of the 2013 Davis Cup.

Chiudinelli then received a wild card into the 2016 Swiss Indoors tournament where he took on compatriot Stan Wawrinka in the first round and lost in three sets 7–6(7–1), 1–6, 4–6, despite leading the match against the newly crowned 2016 US Open champion.

In 2017, after an injury plagued-season, Chiudinelli announced on his website that he would be retiring following the 2017 Swiss Indoors tournament where he enjoyed the greatest success of his career, reaching the semifinals in 2009.