Inter manager Christian Chivu refused to blame goalkeeper Yann Sommer following a disappointing derby defeat to AC Milan, instead praising his team's overall performance and spirit. The Romanian coach also strongly defended his decision to substitute captain Lautaro Martinez early in the second half of the 1-0 loss, insisting the call was tactical and within his rights as manager. Inter now sit fourth in Serie A after their fourth defeat of the season.Chivu's first Derby della Madonnina as Inter coach ended in a narrow defeat to city rivals AC Milan, courtesy of a Christian Pulisic goal in the 54th minute. Despite the disappointing result, Chivu expressed satisfaction with his team's effort and application. "The performance and focus were there, we didn't suffer any counterattacks," he said. "The only time we went for a long ball, Milan scored. But I'll take credit for the good performance from the lads who tried in every way. That's the spirit I want to see."Inter dominated possession with 64% and managed 16 shots to Milan's eight, with five on target compared to Milan's three. They also won nine corners to Milan's one, highlighting their territorial advantage. However, wasteful finishing, including two shots hitting the woodwork and a missed penalty, ultimately cost them the points.Milan's goal came after Inter goalkeeper Sommer got low to stop a shot from Alexis Saelemaekers, knocking it into the path of Pulisic for an easy finish less than 10 minutes into the second half. Despite the spill, Chivu held off of criticising the shot stopper."I'm not talking about individuals, that's not fair. For me, my players are the best, and I could never point the finger at anyone because when you do that, it smells like failure," he said. "We're all in this situation: we could have unlocked it, done better, managed it, but the statistics are what they are. We just have the duty to get back up."Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights with GOAL Tips on Telegram. Join our growing community now!A key talking point from the match was Chivu's decision to substitute captain Martinez in the 64th minute, just 10 minutes after Milan took the lead. The Argentine forward has been a pivotal player for Inter, and his early withdrawal drew questions.Chivu, however, was defiant in his defence of the decision, emphasising it was a tactical choice and not due to injury or poor performance, saying: "Lautaro is fine, it was my decision. He's fine, I took him off for my own technical reasons: can't I change players? Even those on the bench deserve to contribute. It was my decision."The defeat leaves Inter in fourth place in Serie A with 24 points from 12 matches, three points behind league leaders Roma. Chivu acknowledged that the number of defeats is a concern for a club with title ambitions."It's clear that four defeats in 12 games is too many. The table is tight, we need to let go of disappointments and overcome frustration, which can leave its mark. I know how much we create and how much we concede," he added."Due to my team's characteristics, we attack with many men, and that exposes you to counterattacks. But today we only conceded one, which was fatal. We need to work, improve, better perceive danger, and earn a few more yellow cards."Inter have now lost three of their last five Serie A matches, a run of form that will need to be addressed quickly to stay in contention for the Scudetto.Following this derby defeat, Inter will look to bounce back in their next Serie A fixture against Pisa which comes right after their Champions League clash against Atletico Madrid. Chivu's side will need to translate their dominance in possession and chance creation into goals and wins to climb back up the standings. The manager will also be looking for a reaction from his players, particularly in terms of defensive solidity and finishing, to avoid further slip-ups.