Steve Potts knows a thing or two about keeping clean sheets.
The West Ham United legend played more than 500 first-team games between 1985 and 2001, helping the Hammers to keep a club record 16 Premier League clean sheets in 1998/99.
Fifteen years on and Potts is now the Club's U18s manager, while the modern-day first team are chasing that record, having blanked their opponents in 13 of their opening 27 league matches.
"I think the clean sheets have probably been the key to everything, really," said Potts, who was a versatile defender and won Hammer of the Year in 1993.
"If you can keep it tight at the back, then you always have a chance in games and, in the Premier League, unless you keep it tight at the back teams will score goals against you.
"If you keep a clean sheet, one goal will win you the game and that's what they have done lately."
With Winston Reid back from long-term injury, West Ham now have strength in depth in the centre-back position - a situation Potts is pleased to see.
"I thought, at the start of the season, that the squad looked strong and we had good cover in all positions. Obviously, it was difficult because all the injuries disrupted a lot of things, including confidence.
"You can see what confidence is doing now, because they're all on a high and there is competition for places as well, which is also important."
After a perfect February, West Ham now embark on a tricky March fixture list that involves trips to Everton, Stoke City and Sunderland and home games with Manchester United and Hull City.
Potts says it is important that the squad maintain the momentum they have built up over the last five matches.
"They have bought themselves a bit of luxury in that they go to Everton hoping to keep it going, rather than going there desperate to get a win. They've had some great results recently and maybe the pressure is off a little bit.
"Everton are a good team, but you never know. Hopefully they can get something up there and keep it going. It's been good lately."