Chelsea 2 - 2 Swansea: Courtois sent off as Swansea stymie Chelsea

The inclusion of Costa -- and Courtois, who recovered after picking up a knee injury in the warm-up -- meant the Chelsea starting line-up carried a familiar look with new recruits Asmir Begovic and Radamel Falcao named among the substitutes.

Chelsea's failure to make more signings in the wake of last season's success has prompted accusations the club risk standing still while their main rivals have strengthened.

Mourinho defended the approach in the build-up to this game, although he admitted he still wants to bring in a left-back to challenge Cesar Azpilicueta following the departure of Filipe Luis.

Initially it appeared to be business as usual on the pitch, with the hosts quickly hitting their stride against a Swansea side anxious to avenge the two heavy defeats they suffered at Chelsea's hands last season.

Garry Monk's side shipped nine goals in those two games, but after finishing eighth last term, the Welsh side are confident of making further progress, particularly following the addition of Ayew from Marseille.

An early header from Gomis flashed across the face of Courtois's goal to confirm the visitors' threat.

- Montero dominates Ivanovic -

Then the Swansea striker was too slow to make the most of a good 15th-minute chance after being set up by Jonjo Shelvey.

But it was Chelsea who began to dominate the game with Oscar, operating behind Costa, at the heart of most of the home side's attacking moves.

And they took the lead when Gomis conceded a free-kick on the left-hand angle of the Swansea penalty area following a clumsy challenge on Azpilicueta.

Oscar whipped in a low cross that eluded everybody and drifted inside the far post.

Swansea responded positively and were level six minutes later when Jefferson Montero eased past Branislav Ivanovic before crossing for Gomis, whose header brought an excellent diving save from Courtois.

Ayew was on hand to pick up the rebound and he finished cleverly from close range after his initial effort had been blocked by Gary Cahill.

Unfortunately for the visitors, they did not remain on level terms for more than a minute with Chelsea restoring their lead when Willian's left-wing cross was deflected into his own net by Swansea centre-back Fernandez.

However, Swansea never allowed their belief to waver and were given encouragement by Montero's complete dominance of Ivanovic, which ensured that Chelsea were unable to close the game down.

And they were rewarded with a second equaliser when Shelvey's through ball released Gomis -- played onside by Willian -- and prompted Courtois's rash challenge on the striker on the edge of the box.

Oscar was sacrificed for Begovic, who was sent the wrong way by Gomis as the striker finished calmly from the spot.

The balance of the game shifted, with Swansea dominating and Chelsea forced to hang on until the final whistle brought relief to Mourinho and his players.