Former Indian spinner Murali Kartik believes head coach Gautam Gambhir will be under tremendous pressure after the side's embarrassing home series loss to South Africa. After losing the opening Test in Kolkata by 30 runs, India suffered a massive 408-run defeat in the second Test in Guwahati.The 0-2 debacle was India's second home Test series whitewash since Gambhir took over as head coach last year. They endured a 0-3 setback in the home Test series against New Zealand in 2024.The 408-run margin of defeat in Guwahati was also India's worst in terms of runs in Test history.Talking about India's poor showing in Tests under Gambhir and the series loss to the Proteas, Kartik said on Cricbuzz (12:12):"There is a lot of pressure on poor Gambhir. But this is the same coach under whom you won the Champions Trophy and drawn in England. Yet, only two series won out of six and that was against Bangladesh and the West Indies so the pressure is mounting. When we lost 0-3 to New Zealand, we had Virat, Rohit and Ashwin and didn't fare well. We didn't play well at all."He continued:"Now this is a young team so is that an excuse or do you still say when you can win other tournaments, why not at home? We need to find the right personnel. I don't think suddenly dropping the coach is the answer. Because it's not as if they've not won under him."Under Gambhir, India have lost three out of their six Test series, with the only two series wins coming at home against Bangladesh and the West Indies."Has to work out his technical flaws and maybe even certain temperamental flaws" - Murali Kartik on Sai SudharsanMurali Kartik expressed his disappointment in Sai Sudharsan for his poor showing in the second Test against South Africa. The left-hander was dropped from the series opener but scored only 29 runs across the two innings on his return in the Guwahati outing.Sai has struggled to make an impression in his young Test career, averaging only 27.45 in six matches."It's about finding the right people and persisting with them and having the patience with them. That's the way forward. I actually thought Sai Sudharsan would be a great addition to the side. But he has to work out his technical flaws and maybe even certain temperamental flaws. Today he just got into a shell or a muddle and didn't put away balls he should have," said Kartik (via the aforementioned source).The former spinner was also unimpressed with Dhruv Jurel's showing, saying:"Dhruv Jurel batting so well down the order suddenly gets bumped up the order and everybody felt he can get picked just as a batter alone. But given that responsibility, he hasn't got runs in this series. I know the pressure is on Gautam but we need to get the right personnel and have a thorough gameplan going forward."Despite entering the series in red-hot form, Jurel finished with a woeful average of only 7.25 in the two Tests against South Africa.