Shaun Wright-Phillips claims Chelsea have become a true team since Frank Lampard was replaced, and that makes them a major threat to Manchester City in Saturday's FA Cup semi-final.
The former England winger will have divided loyalties for the Wembley clash, having played for City in two stints either side of a three-year spell at Chelsea.
Wright-Phillips won the Premier League and FA Cup while with Chelsea, playing for the London club alongside club legend Lampard who went on to have 18 months as manager before being dismissed in January of this year.
Thomas Tuchel has brought a more pragmatic approach since being appointed as successor to Lampard, not foregoing the element of fantasy but placing a greater emphasis on industry, with the hard work paying off.
Chelsea are through to the Champions League semi-finals and could yet meet City in the final of that competition, with Real Madrid and Paris Saint-Germain standing in the way of the Premier League pair.
"I think what Chelsea have brought to the table now is a resilience," said Wright-Phillips, speaking to Stats Perform News.
"I've seen a lot of their games. I believe they've not necessarily blown teams away, but they're starting to keep clean sheets and they're taking their chances.
"But there are opportunities there to be exploited which I have seen in games, and the teams that have had them haven't really taken them."
The 39-year-old Wright-Phillips says some of the early-season verve has gone from Chelsea's play, but for good reason.
"I must say they're not as exciting and free-flowing going forward, but they're defending a lot better as a unit, as a team, and they're pressing as a team rather than as individuals," he said.
"He's got them defending with a lot of discipline which has been hard to break down for a lot of teams, so I think if you can stop conceding goals, as for example City have, it does take a lot of pressure off your attackers to have to force situations.
"They can learn to be more patient based on the fact they have massive belief in their defenders and they don't need to rush anything, because they know if it doesn't work out then our defenders are going to keep a clean sheet."
Chelsea have underperformed in terms of finishing off their chances under Tuchel, scoring just 12 goals in the Premier League from an xG (expected goals) total of 16, but at the back they have kept it tight, conceding seven times from an xGA (expected goals against) of 6.6.
Those Opta figures exclude penalties, with Chelsea having scored four and conceded no spot-kicks across the 12-game span, and own goals, of which they have scored one and let in one.
A 5-2 home defeat to West Brom on April 3 ended a run of 14 games unbeaten since Tuchel assumed the role of head coach, but Chelsea have got back on track since by thrashing Crystal Palace 4-1 and edging out Porto in the Champions League quarter-finals.
Wright-Phillips sees "a lot of firepower" in the Chelsea ranks yet believes they have become "very, very solid", pointing to the example of "outstanding" centre-back Antonio Rudiger, a colossus in defence for Tuchel.
Since January 26, the date of Tuchel's appointment, only Chelsea team-mate Cesar Azpilicueta has had more clean sheets among Premier League defenders than the seven achieved in 10 games by Rudiger, with Azpilicueta's eight coming from 12 league appearances.
In the same period, Rudiger is one of only five Premier League defenders with 300 minutes or more of action to have made at least 15 tackles and won 70 per cent or more of such challenges in the competition. Sheffield United's Jayden Bogle, James Tarkowski of Burnley and Leicester City's Wesley Fofana and Ricardo Pereira are the others.
The battle between rival coaches Tuchel and Pep Guardiola is bound to intrigue, with City having been surprisingly beaten by eventual cup winners Arsenal at this stage last season.
Wright-Phillips is relishing the clash in styles, predicting the reinvigorated Chelsea will look to break at pace after soaking up City pressure.
He said: "It makes for an interesting game. They don't mind not having the ball, whereas City love having the ball, so they'll most likely play on the counter-attack against City."