This wasn’t the way Thomas Tuchel drew it up. After Chelsea had spent £350million in the last two summers, it wasn’t supposed to be two players who couldn’t find new clubs and another who couldn’t find the net that bailed him out of his toughest week in west London.

But after two 1-0 defeats in a week saw Tuchel’s plan A hit the buffers, it was Chelsea’s unlikely lads who kept him on track.

Ruben Loftus-Cheek and Ross Barkley spent last season on loan at Fulham and Aston Villa respectively, and even Tuchel had admitted he didn’t see much future for them at Stamford Bridge.

Timo Werner, meanwhile, hadn’t scored a league goal for six months and when he thought he’d ended his drought here in the 41st minute, VAR said otherwise.

But Tuchel needed a refresh after those losses to Manchester City and Juventus in which Chelsea had one shot on target across 180 minutes and saw record signing Romelu Lukaku nullified.

Out went Kai Havertz, Hakim Ziyech, Jorginho, Andreas Christensen and Marcos Alonso, but there was still no place for summer arrival Saul Niguez, with Loftus-Cheek trusted instead.

The fact that Tuchel had to rely on Loftus-Cheek to make his first league start for Chelsea in 383 days emphasises how the German has had to think again after the first major bump in the road since he was appointed in January.

Loftus-Cheek repaid his faith with an assured performance in central midfield, while Barkley played a key role in Werner’s goal to make it 2-1, seconds after coming on in the 83rd minute.

‘I always make my choices for the best of the team,’ said Tuchel. ‘There will be tactical choices, choices of current form, of connections on the field. Saul was very, very close to starting today, but I decided against it. I thought if we put him in another high-intensity, pressing opponent, would it be fair to say prove it, let’s see if you’ve gone further.

‘I had to make the selection today and eight players (on the bench) didn’t like it, but that’s life at Chelsea — we have to keep everybody positive and working. Guys have to work for their form because performances are the most important thing.’

Of course, turning to the reserves tends to be easier at Chelsea. Loftus-Cheek and Barkley have a combined 43 England caps and the surprise at £47million Werner’s role in this victory comes more at his run of two goals in 32 league games before Saturday.

Tuchel denied that he was feeling the pressure of being European champions and early title favourites, but signs of frustration at the week just gone were showing when referee Martin Atkinson chalked off Werner’s header from close range, after VAR Mike Dean alerted him to a foul by Cesar Azpilicueta in the build-up.

The Chelsea boss was so incensed at the decision that he received a yellow card from Atkinson. ‘I got emotional and the ref told me he cannot accept that. It’s fair enough,’ said Tuchel.’

Southampton manager Ralph Hasenhuttl had his own disagreement with the officials when James Ward-Prowse was sent off for a late challenge on Jorginho. Earlier the midfielder had given Saints hope of a more positive result with a penalty to make it 1-1 after Ben Chilwell had fouled Tino Livramento.

Relief for Chelsea came thanks to Barkley’s immediate impact, threading a pass into the inside right channel for Azpilicueta, who squared first time for Werner. Even the profligate German could not miss from four yards.

Ben Chilwell, another Chelsea player making a rare appearance in the starting line-up this season, sealed victory in the 89th minute.