The French forward, sidelined since late September with a hamstring problem, came off the bench in the 71st minute to inject fresh energy into a Nerazzurri side that had been forced to dig deep after a strong start unravelled.
Inter had looked on course for a comfortable night when Lautaro Martínez and Hakan Çalhanoglu struck early to make it 2-0 inside the opening 20 minutes. But Kairat, the Kazakh underdogs playing in their first Champions League campaign, hit back before half-time through João Paulo's stunning strike, turning the game into a nervy contest.
Thuram's introduction gave Inter renewed urgency. The 28-year-old nearly capped his return with a trademark header from a corner that flew narrowly wide, a reminder of the physical presence and attacking instinct the Italians have missed in his absence.
Before his injury, Thuram had been one of Inter's standout performers, scoring three goals and providing an assist in six appearances across all competitions. His absence forced coach Cristian Chivu to experiment in attack during a demanding run of fixtures.
Chivu had hinted before the match that Thuram's involvement would depend on fitness. "He is fine," the Inter boss said earlier in the week. "He is called up, but we must evaluate carefully, we want him 100 percent and we must not take risks."
The timing of his return could not have been better. Inter's win stretched their unbeaten run to four matches and kept them top of the Champions League league phase on 12 points. Full-back Carlos Augusto summed up the relief afterwards: "Everyone expects us to win 5-0, but there are no easy games in the Champions League. What mattered was winning."
For Thuram, the comeback also boosts his international prospects ahead of France's crucial World Cup qualifiers against Ukraine and Azerbaijan later this month. Didier Deschamps will be encouraged to see his striker regaining rhythm after a summer in which he starred at Euro 2024.
Inter now prepare for a Serie A clash with Lazio on Sunday, and with Thuram back in contention, they look better equipped to handle the grind of a long season. Wednesday night was a timely reminder that this Inter side thrive when pushed to the limit.
Real Madrid are closely tracking the progress of academy graduate Jacobo Ramon, whose impressive form in Serie A with Como has caught the attention of head coach Xabi Alonso.
Luciano Spalletti's arrival at Juventus on October 30, has brought renewed belief and direction to Turin, with the veteran coach already stamping his authority after replacing Igor Tudor.
Strasbourg's on-loan defender Mamadou Sarr has chosen to represent Senegal at international level despite having represented multiple France youth teams.
Barcelona's mounting injury list has grown longer after defender Eric Garcia was diagnosed with a nasal fracture following their dramatic 3-3 draw with Club Brugge in the Champions League on Wednesday night.
