The Blues returned to their home ground on the back of defeats to Celtic, Manchester City and Real Madrid, a victory against Club America and a draw with Wrexham in their first five friendly matches.
Despite a particularly dominant first 45 minutes for the hosts, the Italian side scored the opening goal of the game thanks to a sumptuous strike from Thuram in the 26th minute.
Chelsea were the better team throughout the entire 90 minutes and created plenty of chances worthy of an equaliser against their opponents, but it took until the 90th minute for Ugocukwu to finally level the score with a volley from inside the area.
The result will mean little to Enzo Maresca, but the performance showed plenty of signs of promise ahead of their Premier League season opener next weekend.
Chelsea fail to capitalise on promising first half display
Having failed to impress in a majority of their pre-season fixtures, often falling to disappointing defeats such as their 4-1 loss to Celtic, Chelsea looked unlikely to cause the Italian champions much trouble ahead of the encounter.
However, that was far from the case with the hosts putting together numerous fast-paced, passing moves that took Inter Milan apart, but the Blues failed to capitalise on their chances.
Maresca would have been happy with his side's 54% of the ball, much of their passing play happening in the opposition half, while his men also took nine shots to Inter Milan's two.
Summer signing Marc Guiu was especially impressive in the first 45 minutes, coming close to hitting the net on several occasions only for Yann Sommer to pull off an excellent save to deny the Spaniard.
After all of Chelsea's good work in the first half, they still found themselves, rather unfortunately, heading into the half-time break 1-0 down after Thuram scored one of Inter Milan's two shots, a wonderful left-footed strike into the top right corner.
Chelsea's defensive vulnerabilities persist
Chelsea's frailty in the defensive areas has been apparent throughout the entirety of their pre-season preparations ahead of the 2024-25 Premier League campaign, and that continued in their final friendly against the Nerazzurri.
Despite most of the match being played in the Italian side's half, Inter Milan looked especially dangerous when they were willing and able to break out from the back.
Thuram's first-half goal was the perfect example of Chelsea's defensive weakness, with Yann Bisseck able to step into the midfield and charge towards Chelsea's goal without any Blues player challenging him.
Bisseck played it on to Joaquin Correa, who subsequently passed it through to Thuram, with the striker allowing the ball to move across his body before firing a left-footed shot into the net, an entire move without a significant challenge from a Chelsea player.
Inter Milan had several other similar chances, breaking out from the back with ease and moving into the forward areas, and on another day where the Nerazzurri were more clinical, Chelsea could have found themselves a number of goals behind.
Vital first minutes of pre-season for Chelsea's stars
Among the positives that were on display, alongside the quality of the chance creation from Maresca's side, was the Chelsea players who managed their first minutes of pre-season for the Blues.
Marc Cucurella returned for his first minutes, playing the first 45, for Chelsea since being part of the Spain side that won the 2024 European Championships.
Cole Palmer also made an appearance for the first time since suffering defeat in that final, coming on in the second half and playing a big role in the equaliser from Ugochukwu in the final minute of the game.
Nicolas Jackson was the last player to earn his first time on the pitch in pre-season, coming on in the 56th minute for Guiu after the Spaniard pulled up with a potential injury, meaning Jackson could be in line for a start next Sunday.
What next for Chelsea and Inter Milan?
The draw against Inter Milan was Chelsea's final pre-season match in preparation for their Premier League season opener, where they will face Manchester City at Stamford Bridge at 16:30 on Sunday.
As for Inter Milan, their next match will be the beginning of their Serie A title defence as they come up against Genoa on Saturday at the Stadio Luigi Ferraris.