The Sydney wildcard kicked off the Aussies' 11-strong singles challenge on a humid Sunday morning at Roland Garros with high hopes, only to depart Court 8 deflated by a 6-2 6-4 6-7 (7-5) 6-1 first-round loss to Slovenian Aljaz Bedene.

O'Connell had been hoping for more grand slam success after his breakthrough performance at the Australian Open when he reached a career-best third round and earned his biggest win over then world No.13 Diego Schwartzman.

So the 27-year-old felt he'd missed a serious opportunity after getting what he'd thought was a favourable first round draw against a player who's ranked 51 places below him.

But a double fault on the first point of the match quickly set the tone as he dropped serve immediately en route to being largely outplayed over the first two sets.

Yet the slow-starting world No.124 O'Connell demonstrated considerable resistance in the hour-long third set, going on the offensive and eking out 11 set points before finally taking the tiebreak.

It set the scene for a potential comeback like the one the 27-year-old O'Connell got so close to pulling off in the first round against American Tommy Paul last year, fighting back from two sets down to take the contest into his first-ever five-setter.

O'Connell went on to lose that one and declared himself "devastated" - but there was no chance of repeat fifth set drama this time as Bedene raced into a 5-0 lead in the fourth and sealed the match in two hours 48 minutes.

"It was pretty much like last year," sighed O'Connell. "I've been playing some good tennis and I just didn't really show that out there today and that's really disappointing.

"Every loss is tough, but I'm really disappointed, I thought I had a good draw - but he's probably looking at me, thinking he's got a good draw too, up against a wildcard ranked outside the top 100.

"I guess he'd just showed his experience a little more."

Australian Associated Press