Tomorrow could be the biggest day yet, with the football team playing away to Bosnia-Herzegovina in a match that may see them qualify for next year’s European Championship in France.

The rugby union side, meanwhile, heads to Twickenham for a showdown with Australia, having already qualified for the quarter-finals of the Rugby World Cup, at the expense of tournament host England.

Even if they don’t do enough in Zenica, it would be a huge shock if Gareth Bale and team-mates failed to secure the country’s berth at a first major championship since 1958 three days later, in what promises to be a joyous final group home fixture against tiny Andorra.  

Yes, they have been helped by expansion of the competition format for the first time to 24 teams.

But, as I write this, Wales sit top of a group that bracketed them with arguably the most talented Belgian squad there has ever been, so they might well have qualified anyway.

Their recent results have been consistent enough to propel them to an improbable eighth in the FIFA rankings, a couple of notches above England, making them the fifth-best current European team.

I would not though wish to give the impression that the Welsh sporting renaissance is limited to these two team sports.

To cast the net just a little wider, double Olympic gold medal cyclist Geraint Thomas goes from strength to strength, helping Chris Froome to victory in the 2015 Tour de France, reaching as high as fourth in the Grand Classement before finally weakening on the 19th stage and ending up 15th, still a career best.

And then there is Denbighshire’s Jade Jones, the first British Olympic gold medallist in the ancient Welsh martial art of taekwondo.

The 22-year-old followed up this success at London 2012 with gold at the inaugural European Games in Baku this summer.

So the Cymru sports renaissance is undoubtedly a thing – what is harder to establish is what has triggered it.

Looking at these four outstanding examples, it seems to me difficult to identify a common thread.

Rugby: it’s the national sport; it’s in the blood; there is always likely to be an abundance of talented youngsters within the confines of the country’s relatively small three million population.

The present squad, as usual, is talented, even allowing for the recent spate of injuries depleting its ranks; but few would, I imagine, put it on a par with the brilliant Welsh teams of the late 1960s and 1970s.

What I think has made a difference, and given the squad a shot at reaching a second consecutive World Cup semi-final, is Wales’s outstanding (partly non-Welsh) coaching team.

New Zealander Warren Gatland, the head coach, strikes me in some ways as the Kiwi Mourinho, while Englishman Shaun Edwards, one of his assistants, is one of those who has brought the defensive strategems of rugby league, where you have two players fewer to cover the ground, to the 15-a-side game.

I have plenty of respect for Chris Coleman, the football manager under whom Wales are blossoming, but I would not yet see him as quite as critical to his team’s success as Gatland.

The sine qua non of Wales’s footballing progress (not unlike 1958) is a single world-class player – Bale – who appears supremely motivated when he dons his country’s red shirt.

The achievement of Coleman and the rest of the squad – and it is no small thing – is to have built an efficient, and proficient,  platform giving the Real Madrid man the support he needs to make the difference.

We talk a lot in Britain of “club versus country”, generally arguing that the success and demands of the Premier League make it harder, allegedly, for the England team to excel.

In Wales, however, it seems to me that the extraordinary progress of the nation’s leading clubs has been a big help in the rise to prominence of the national team.

I well remember on the eve of the 1999 Rugby World Cup final (in Cardiff), being taken to watch Swansea City beat Halifax Town 3-1 in the fourth-tier of English football.

The club’s ascent since then has been extremely special to behold, particularly if you take into account the rapid establishment of a distinctive Swansea school of possession-oriented, passing football.

The inculcation into this style of play of the likes of Ashley Williams, Joe Allen, Neil Taylor and Ben Davies has provided critical underpinning to Bale’s brilliance in the national side.

Swansea’s South Wales rivals Cardiff City have enjoyed a season in the Premier League in recent times too, and while they are back now in the second tier, they also have unearthed important players for Wales, such as Aaron Ramsey and Joe Ledley .

As for the successful Olympians, Thomas and Jones, they have been among the beneficiaries of a golden age of Government and National Lottery investment in British Olympic and Paralympic sport, inspired by London 2012.

Thomas is also one of the generation of British cyclists who have been able to draw on the coaching/management expertise of Sir Dave Brailsford, a figure revered at least as highly in his field of operations as Gatland in his.

So is it a coincidence that all this success has arrived at around the same time? I consulted two authorities on Welsh sport.

Dame Tanni Grey-Thompson, the wheelchair racer who amassed no fewer than 11 Paralympic gold medals between 1992 and 2004, highlighted one factor that can certainly spread from sport to sport: confidence.

“I think at the moment there is a massive confidence in Welsh sport,” she said.

She also pointed to the potentially inspirational effect of the Commonwealth Games, an event at which a multi-sports team competes as Wales, unlike the Olympics and Paralympics.

“We are a small nation and things like the Commonwealth Games help inspire in a different way to the Olympics because geographically you are closer,” she said.

Thomas, of course, won the road race in the scarlet of Wales at the 2014 Commonwealth Games in Glasgow, where the country achieved its best-ever medals haul of 36.

Martin Johnes, a Swansea University lecturer and author of A History of Sport in Wales, concurred that it was difficult to identify a common thread in the nation’s recent sporting success stories.

He pointed to the role that can be played by luck, particularly in team sports, arguing with respect to rugby, that it was “hard to point to anything different” between the 1960s and the 1970s, except that in the latter decade the sport had benefited from the “historical accident” of talented individuals coming through at the same time.

After chewing over the issue, we did identify good administration as a possible common theme across sports.

“The Football Association of Wales (FAW) is probably more professional than it has ever been,” Johnes said.

“Welsh sport at the moment seems very well administered, well run, well managed.

“We should never underestimate the importance of such things."