Saints weathered an early storm and then got the settled down to a workmanlike performance to ensure that they don't go into second leg at St Mary's on Friday playing catch up.
Russell Martin's team line up was pretty much as expected when it was announced an hour before kick off, the only real surprise was Sekou Mara in at centre forward and with Che Adams injured.
From the first whistle West Brom were on the offensive, Saints were finding it hard to find their shape and any sort of rhythm, it was crucial that we dug in and didn't concede and that is what we did and then slowly started to impose ourselves on the game.
Once we had done that we mainly controlled the game, although Alex McCarthy was the busier of the two keepers and had to pull off a superb save from a close range header to keep the scores level at half time.
Like the recent victory at Leeds you felt that this was a Saints team with organisation and spirit and one that was not going to lose this game.
At the back we were well marshalled with Jack Stephens playing his left back/central midfield hybrid role again, the midfield worked hard and so did the front line.
Sekou Mara was having a rare start and finding it tough going, but he worked hard and although being the whipping boy of some fans, didn't let the team down in what was the most important game of the season.
Russell Martin was the first manager to blink when he made the first substitution of the game on 71 minutes, on came David Brooks, Ryan Fraser & Ross Stewart, a little strange to change what was essentially the entire frontline, but Martin perhaps felt that we were comfortable in defending and wanted fresh legs to try and win the game in the closing stages.
All in all though this was a satisfactory performance, we look more like the team that went 22 League games unbeaten now, than the inconsistent performances that saw goals leaked and games lost in the aftermath of that run.
But we have got the first half of the semi final out of the way unscathed, now we have to finish the job at St Mary's
The travelling Saints supporters were magnificent, the home fans started the game like their team, they were frenetic and a sea of noise and colour on all four sides of the stadium, with just the 2,000 strong enclave of Saints fans in one third of the Smethwick End, but the Southampton fans took inspiration from their team and weathered the noise and then imposed themselves with some great backing.
There is a lot of talk about the Northam being a Red & White wall next season, but it needs to be that on Friday evening and indeed on all four sides at St Mary's we need to show the West Brom fans that we can match the atmosphere of noise and colour that they created on Sunday.
Near the end I reflected on the first time I visited the Hawthorns, that was on February 14th 1976 in the FA Cup 5th round, nothing of the stadium then is left, over the years it has been completely rebuilt, but the one thing that was the same now as back then, was the result, then it was a 1-1 draw and this time 0-0, our season then ended in glory at Wembley in the FA Cup, can history now repeat itself !