A rain-drenched Chadwell Heath did nothing to dampen his new team-mates' spirits, and Les says that the 'mood in the camp' - that well known barometer of how things are at a football club - is excellent despite West Ham's bottom placing.
"Without a shadow of a doubt the spirit is good. I have been in this situation before with QPR and the heads go down, but I have trained with the lads today and you do look around and say 'how are they in this predicament?'
"But the table doesn't lie. With what we've got I feel that this club has got enough to get out of it but it is easy saying that and we have to put it into practice.
"You do usually find the spirit is quite low in this situation, but it has given me a bit of a lift knowing I am going into that game tomorrow with everyone battling for each other."
Les, like Lee Bowyer the week before him, could have opted for an easier life than a relegation battle in east London - and, unlike Lee, Les did not have the excuse of being a Hammers fan!
"I still want to play football and I wanted to challenge myself," he insists.
"A lot of people have said the same thing to me - that I could have taken an easy option, and there were other sides that came in for me not facing relegation.
"But I have seen the quality in this side, having seen them play and the fight that they have got.
"I felt it would suit me the way I play football and that it would be good to try and help.
"The motivation for me is wanting to play football and that is the only motivation I need - being involved in the side and looking to do something.
"As people know I have been a Tottenham fan since I was a boy but that has got nothing to do with it - you go to where you can play football.
"There were a few clubs that had come in but I made my decision a while ago about where I would be best suited to play and where I would enjoy it most.
"Although we are rooted to the table at the moment I can see that with the quality they have got in the side and the passion that the lads have shown in the last few days we can work ourselves out of this predicament."
Neither is he bothered by the fact that the team bottom of the Premiership at Christmas has always gone down by the end of the season.
"That doesn't bother me at all. It is historic and in history things change - we can change the record, and we are in a position to with what we have got here.
"As I said, I went out there expecting a few heads to be down but there was a buzz about the place and hopefully we can take it into the game tomorrow."
Les knows he has tough competition with the impending return of Paolo Di Canio and Fredi Kanoute and he adds: "Fredi and Paolo are coming back, there is Jermain here and he has been doing fantastically well since everyone has been injured, and that competition is good for the side.
"It will push everyone - and that is what you need when you are in this predicament, pushing people on all the time."
Les is open minded about what will happen at the end of the season - he has signed a short term deal until the summer - but has not ruled out continuing to perform at the top beyond 36.
"I want to play until the end of this season to see how I feel and if I am still enjoying it, and if I am we'll look at what my options are then," he says.
He is just glad that the saga of his move, which had dragged on behind the scenes for some time, has been concluded at last.
"It has been going round in circles for quite a while but I am glad it is over now and I can get my head down to concentrate on the job in hand."
Glenn Roeder's persuasive powers helped influence Les' decision to say yes, and he adds: "I spent some time with Glenn during my England days. He is a good man, he knows what he wants, and speaking to him swayed my decision as well.
"I know what he wants for West Ham and hopefully I can help to achieve that.
"You want someone that has got passion and wants to see their club do well - that is what he wants, and he felt I could lend a helping hand."
But he denies coming to the Hammers just so he wouldn't be the older statesman at the club - after all, Nigel Winterburn has nearly three years on him.
"Someone mentioned that to me - did I only join because Nigel is here but don't forget Teddy at Spurs is a little bit older than me as well."
At the other end of the age range is cousin Anton, and he adds: "He pushed me over at one stage in training today - hopefully he will go all the way like Rio."
As a confirmed Spurs fan, wouldn't he rather have made his debut against Arsenal on Sunday?
His three match suspension for being sent off against Arsenal reserves last month had ended and it wouldn't have been beyond the realms of possibility.
"It was one of those games you don't want to miss - but I am here now, and let's get on with the job."
As for thar 'Sir Les' nickname, he is not insisting on it following him to Upton Park, and he smiles: "Call me what you like! It stems back from my QPR days - they all started calling me that while I was there when we finished fifth - and it has just followed me wherever I have gone to."
If Les can help West Ham survive, he will be able to choose whatever title he wants...