Mental toughness has been key to Northern Ireland's clean sheets - Hughes
Veteran Aaron Hughes has attributed Northern Ireland recording seven clean sheets in eight World Cup qualifiers to their mental toughness.
Czech Republic were the latest country that failed to break down a resilient Northern Irish defence as goalkeeper Michael McGovern passed the 10-hour mark without conceding an international goal in Monday's 2-0 success.
No other European nation can boast as many clean sheets as Northern Ireland in this campaign and it has been a huge factor behind them guaranteeing second spot in Group C, and ensuring they will almost certainly be one of the eight play-off teams in November.
Their latest clean sheet was kept without injured Premier League pair Gareth McAuley and Craig Cathcart, and against a team that enjoyed 72 per cent possession, with Hughes impressed by how Northern Ireland again remained alert throughout.
Speaking to Press Association Sport, the Hearts defender said of the Czechs: "They move the ball so well, they shift you from side to side.
"It's as much a mental game as it is a physical game then. You've got to be switched on for 95 minutes and I thought we were fantastic in that respect, no one switched off at all, everyone did their job right until the end and that's what got us the result.
"It shows the strength in depth and not only that I think it shows the concentration levels from the lads coming in and picking up on what we've been working on.
"It is a short time to work on things and to take all that information on board over the three days. A lot of it is repetitive from past games but you've still got to take it on board and do it and it's testament to the lads' work ethic in the squad."
Though manager Michael O'Neill shifted to a back five in the second period, Hughes started the game alongside Jonny Evans at the heart of a four-man defence.
And it was West Brom centre-back Evans who scored the opener and picked up the man-of-the-match accolade less than a week after seeing a late move to either Manchester City, Arsenal or Leicester fail to materialise.
"It's very easy to play alongside Jonny, he's very commanding in the line and I really enjoy playing with him," Hughes added.
"In the nature of the game you're maybe not thinking about it but when you get to play with someone of that quality it's always a great thing.
"He seemed really relaxed and I think it's one of those things, maybe you can't affect certain things so you've just got to concentrate and he never once seemed not focussed on what we were doing here. I think his performances showed that."
As for Hughes, he picked up his 108th cap one month before the 20th anniversary of his first ever senior international call-up.
"When you put it like that it sounds crazy, doesn't it," he said.
"It's making me feel a wee bit old! I'm just so happy to be involved in it. It's a great time to be involved in things here, the atmosphere, the group of guys, the work ethic, the professionalism around and the desire to really push forward and be the best that we can be. To be part of that is a great thing."