It wasn't a signing that set pulses racing.

Arriving from relegated Blackburn, Swiss defender Stephane Henchoz wasn't exactly the sort of player to get excited about.

When Liverpool sealed a £3.5m deal for the centre-back, Gerard Houllier was putting into place a vital piece of his Liverpool jigsaw that would go on to lift three major trophies in the season that followed.

But you wouldn't have known it from Henchoz's arrival, and it's doubtful the defender would have it any other way.

Because as good as Henchoz was at heading, tackling and blocking, he was even better and drifting under the radar.

The Reds had been negotiating with Bayern Munich for Marcus Babbel when Houllier switched his attention to Henchoz. Bayern wouldn't budge on a £4m valuation so Liverpool would have to wait, and in the meantime the man from Blackburn would do.

The Lancashire side had been relegated and Liverpool were able to take advantage of a clause in Henchoz's deal to bring him to Anfield.

Liverpool mightn't have even realised it themselves but they'd stumbled across one of the best defensive partnerships in Europe in just one summer.

Sami Hyypia had already arrived for just £2.5m from Willem II, and in Henchoz they found his perfect partner.

While Hyypia was the towering presence at the heart of Liverpool's defence, dominating all those around him, Henchoz would sweep up what remained.

The always-grimacing Swiss international would often look exhausted within minutes of kick-off, but he was an expert at sensing danger and cutting it out.

Hyypia would often overshadow his perfect partner, but it was only outside of Liverpool that Henchoz was underrated.

Henchoz saves from Henry in the FA Cup final
Henchoz saves from Henry in the FA Cup final

Yet even when looking back on the summer of 1999, it's easy to overlook what a vital signing he was.

But Henchoz did not arrive without a certain degree of pedigree.

This was a man who had made his debut at just 17, and at the Santiago Bernabeu, no less.

He'd almost signed for Manchester United, too, but an ankle problem nixed the deal before it could be completed.

In the end it was Roy Hodgson who brought Henchoz to England after the future Liverpool boss had managed him during his time at Neuchatel Xamax and the Swiss national team.

It wasn't an easy start to life at Anfield for Henchoz, who was missing for three months with a groin problem but when he finally got the opportunity he soon forged a rock solid partnership with Hyypia at the back.

Indeed, such was the duo's understanding that when Babbel would follow a year later the German would mainly operate as a right-back for the Reds and young defender Jamie Carragher spent most of his early career at left-back.

The stoic duo just seemed to understand each other, and Hyypia admitted to feeling more secure when alongside his Swiss partner.

"I must admit I feel more comfortable about my own role in the side when Stephane is alongside me," said Hyypia.

"When he is out, it takes more communication with whoever is beside me to make sure everything goes smoothly.

"With Stephane, I don't need to say a word to make it work. Neither does he.

"In fact, we don't even have to think about it now. It is just automatic that each of us knows exactly and instinctively where the other is going to be and who is going to do what.

"As a team, we definitely feel more secure with him around."

And while Henchoz didn't receive many plaudits outside of Anfield, the results told you all you needed to know about how good a partnership were operating at the heart of Liverpool's defence.

The Reds boasted the Premier League's best defensive record in 1999/2000 and 2001/2002, and were third behind Manchester United and Arsenal in 2000/01.

Henchoz had a knack of showing up at big moments for the Reds, playing arguably as important a part in Liverpool's 2001 FA Cup win as goalscorer Michael Owen, even if it was by slightly nefarious means.

Another highlight was truly one of the most remarkable tackles you'll ever see on Fulham's Steve Marlet when the Frenchman was through on goal, as well as an excellent performance against Ruud van Nistlerooy as Liverpool secured their second consecutive 1-0 victory at Old Trafford in January 2001.

Henchoz's Liverpool career wasn't the longest, he burned brightly for three seasons before the Reds declined and injuries took their toll in 2002/03 and 2003/04.

He'd leave the club after Rafael Benitez arrived in 2004 as Carragher established himself at the heart of Liverpool's defence.

He would never score for the club in a competitive game, but he prevented countless goals at the other end of the field.

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Henchoz would depart quietly for Celtic in January, but not before breaking character just once to blast Benitez for freezing him out.

"I'm the king of the exiles here so, as far as I'm concerned, it's finished for me at Liverpool," he said. "In my head it's as if I've already left. Besides, people are treating me as if I don't exist any more.

"No one's shown me any respect and Rafael Benítez, since his arrival, has treated me as if I was the dumbest of the dumb."

It wasn't like Henchoz, who'd done his talking on the pitch at Anfield. But in truth he deserved better than the low-key departure he was given.

He's not a man talked of much at Anfield these days, nor is he discussed in the wider context of Premier League defensive greats.

He was the most underrated of all the underrated, the unsung hero of unsung heroes.

But make no mistake, and just ask his ex-team-mates if you're unsure, Henchoz was as vital to Liverpool's success as anyone.