Two late goals gave FC Basel 1893 a wonderful lift-off in the UEFA Champions League while spoiling José Mourinho's return to this stage with Chelsea FC.
Another masterful finish from Oscar just before half-time maintained his prolific strike rate in the competition and suggested the Blues would be rewarded with their customary first-day victory. However, the ever-dangerous Mohamed Salah curled in a 71st-minute equaliser, Marco Streller then rounding off Basel's fightback with a header from a corner.
This was not the script that had been promised beforehand. Chelsea had never met defeat on matchday one in 11 previous fixtures; indeed, nor had Mourinho in ten past campaigns. But for the strength of their defending when under pressure in the first half and also for their unyielding spirit, the Swiss titleholders deserved this first victory on English soil.
Chelsea gave first starts to summer recruits Willian and Marco van Ginkel and they showed up well as the blue shirts had Basel back-pedalling from the off.
A number of corners followed but worryingly for Mourinho's men no direct threat on the away goal ensued. At the same time Basel showed speed and enterprise on the break to suggest that they could make things difficult for the 2012 champions.
Chelsea began to look sharper around the 25-minute mark, when Frank Lampard took aim and then Eden Hazard made himself room before firing over. It was a finish that Salah matched at the other end after veering inside.
Basel looked to have achieved their first target – namely a clean sheet to take into the interval – when Oscar broke the deadlock. David Luiz ventured forward and fed Lampard, who slid a perfect pass down the side of a defender for Oscar to steer his shot into the far corner.
The Brazilian international now has six UEFA Champions League goals in seven appearances and nearly scored again with a swerving shot that smacked the bar. At that stage it looked like Chelsea could go further ahead, but instead Basel took the opportunity to turn the tables.
A fast, incisive move led to Streller bringing in Salah and his left-footed finish was immaculate. Basel would have celebrated the point; instead they ended up with all three as Matías Delgado's inswinging corner was headed in at the near post by Streller.
In his first Stamford Bridge reign Mourinho had only tasted defeat in one UEFA Champions League home fixture and never in the group stage. The loss will give him food for thought ahead of their matchday two visit to FC Steaua Bucureşti.