James O’Connor admitted he was taken aback by the pace of the English Premiership after making a losing debut for London Irish against title-chasing Northampton on Sunday.

The controversial Australian star, who left his homeland in a bid to resurrect his career following a series of off-field problems, produced a scintillating display at the Madejski Stadium.

But it was not enough to prevent Saints securing a fifth win in seven league games.

The 19-14 away win kept second-placed Northampton within two points of leaders Saracens, who thrashed Newcastle 40-3.

But all eyes were on O’Connor, whose display – just a few days after stepping off a plane to sign with Irish until the end of the season – was praised by director of rugby Brian Smith.

The 23-year-old was delighted to be out on the pitch, but acknowledged the tempo of the match had proved challenging.

“The speed of the game was very surprising,” he said.

“I thought Super Rugby was fast but I was really blowing out there, that’s for sure.

“It felt great. The club and all the boys have been awesome since I arrived and I am really looking forward to my time here.

“I didn’t feel 100 per cent and can get better. I wanted to perform. It was one of the best pitches I have played on. It was just a shame we could not get the win.”

O’Connor, who has amassed 223 points from 44 caps, had his contract with the Australian Rugby Union torn up following his alleged drunken behaviour at Perth Airport earlier this year.

But he took to his new environment in the northern hemisphere like a duck to water, with his rugby skills indicating his signing could prove a real coup for Irish.

He could not stop Saints from continuing their impressive early-season form, though, with fullback James Wilson’s first-half try and 14 points from fly-half Stephen Myler securing victory for the visitors.

O’Connor did set up Irish’s lone try from wing Sailosi Tagicakibau, and fly-half Ian Humphreys kicked the rest of the points as the hosts managed a losing bonus point to help their cause near the bottom.

Smith said: “James was outstanding. He’s 23 and is still just a kid who gets up in the morning and puts his trousers on one leg at a time like everyone else.

“A lot has happened quickly to him but he’s settled in straight away and showed his class today. The boys enjoyed playing with him today.

“We see him as 15, even though many see him as a jack of all trades who has played right along the back line. And he wants to establish himself as a fullback.”