Manchester United defender Chris Smalling is amazed at how quickly striker Robin van Persie has adapted to life at Old Trafford.
Van Persie took his tally at United to 15 goals in 21 games with the opener in Saturday's 3-1 home win over Sunderland.
It is on a par with the legendary Ruud van Nistelrooy's introduction and means the 29-year-old has now scored an incredible 60 times in his last 72 Premier League games.
For Smalling, the achievement is even more remarkable given Van Persie had barely played a pre-season game before he was pitched into his debut at Everton in August, barely 24 hours after completing his £24million move from Arsenal.
"I saw the finish," said Smalling.
"It wasn't easy to put it in that top corner but he is a quality player.
"Obviously he only came in the summer and didn't have much of a pre-season.
"But he came straight into the matches and has been such a threat.
"He is putting teams on the back foot and making our job easier at the back."
Even Sir Alex Ferguson must be slightly taken aback at how well Van Persie has integrated himself into the Old Trafford fold despite the conviction that forced him to abandon an often-repeated need to get value in the transfer market.
"He has a fantastic record," said Ferguson.
"What you are seeing is a player who has come to his mature years.
"Experience is counting for him now. He has the knowledge and ability and last season his form was terrific.
"Even Arsenal, having had him for a few years, were realising what his best position is. We do the same."
Van Persie's latest effort was followed by Tom Cleverley's first Premier League goal at Old Trafford and Wayne Rooney's fifth in four games, even if the England man also wasted a couple of good chances.
Yet, other than the victory that preserved United's six-point lead at the top of the Barclays Premier League which ensured they will still be there on Christmas Day, perhaps the most significant event was the return of Nemanja Vidic.
Plagued by injury for 16 months, during which time he has made only 13 appearances, the Serbian provides the most obvious answer to United's continuing defensive ills.
Although he was partially responsible for Frazier Campbell's goal with an uncharacteristic failure to clear inside his own six-yard box, Vidic cannot be blamed for a sorry return of only four clean sheets all season.
Indeed, he was part of the defence that kept two of them, way back in September.
In pure statistical terms, it is the worst clean sheet return since 1963-64, when United's fifth did not come until their 35th game of the campaign in all competitions.
And the failure yesterday clearly irritated Smalling.
"There was a bit of carelessness, which is disappointing because we wanted to keep a clean sheet," he said.
"Our record with them has not been great and it would have been nice to get one going into the Christmas period."
Evidently there is work to do on that front, although a fully fit Vidic is bound to help.
Presumably though, the bonus is even with such a shaky back four, United have established a healthy position, from which they are favourites to clinch a record 20th championship.
Yet, as Phil Jones is painfully aware, the situation looked even better six games from the end of last season. And that ended in catastrophe.
"We are in a fantastic position, exactly where you would want to be at this stage," said the former Blackburn man, who was starting a league game for the first time this season.
"But last season was my first at United and I experienced something I had never experienced before.
"I learned that in this league, it is never, ever over."