India were gifted a route back into the game when Moeen was caught trying to slog-sweep Ashwin, and 230-3 became 249-5 when Jennings edged to gully and Jonny Bairstow was caught on the sweep.

Former England captain Michael Vaughan said: "It was a tremendous day's play. It's a really good pitch - it's got a little bit of everything but there are runs out there.

"I would say England have just edged that day. Without Ravi Ashwin, India would be right on the back of a terrible day."

Umpire Paul Reiffel was forced to leave the field midway through the afternoon session after being struck on the back of the head by a lobbed Bhuvneshwar Kumar throw from the boundary. The Australian rested for the remainder of the day after a scan.

Reiffel had a scan after being struck on the head by the ball

Jennings punishes India for drop

A former captain of South Africa Under-19s, Jennings made a century for the England Lions in Dubai the week he was added to the senior squad to replace the injured Haseeb Hameed.

He began tentatively but his innings turned round after he edged a short ball from Umesh Yadav on nought and a diving Karun Nair failed to hold on one-handed at gully.

Two balls later he struck his first boundary to get off the mark, setting the tempo of his innings. He mixed easy singles with reverse sweeps and cover drives, looking composed even as he neared three figures.

Watched in the crowd by Hameed, who returned to India with his family after having surgery on his fractured hand, Jennings struck 12 fours on his way to a composed century.

He celebrated calmly after reaching his hundred with a reverse sweep but could not hide his frustration when edging Ashwin to gully shortly after tea.

'The best Christmas present ever' - what they said

Jennings told Test Match Special: "If someone had said to me at the end of September you'd score as many runs as you had and have the opportunity with the Lions, I would have snapped their hand off.

"If someone said to me there would be a Test hundred waiting a couple of weeks later I would have jumped all over it.

"It's been a surreal seven, eight months. To top it off the way it has, with a Test cap and Test hundred, it's the best Christmas present I could get."

Former England captain Michael Vaughan said: "Jennings looked like he could go through the gears - he's got the game. There is a real calm confidence about his play.

"I see a future England team with Jennings and Haseeb Hameed both in, with Joe Root at four."

Former England batsman Geoffrey Boycott added: "He looks nicely composed. He has an economy of movement - he stays very still. His footwork is good.

"Not every day will be good like this but it is a very fine performance. He got to his hundred with a reverse sweep. We didn't even know what it was when I played."

Keaton Jennings became the first England opener since 2006 to hit a century on Test debut

The stats behind Jennings' century

Eighth England opener to make a century on Test debut, and the first since Alastair Cook in 2006

19th England player to make a Test century on debut, and the first since Jonathan Trott in 2009

First England player since Billy Griffith in 1948 to make a century on the first day on Test debut

Four of the last five England batsmen to make centuries on Test debut have been born in South Africa. Jennings was preceded by Andrew Strauss, Matt Prior and Jonathan Trott. Gloucester-born Cook is the exception

Jennings is the 11th opening partner Cook has had since Andrew Strauss retired from Test cricket in 2012. Sunil Gavaskar holds the record for most opening partners, with 19

Keaton Jennings' wagon wheel shows he scored his runs all around the ground

Late wickets take shine off England's day

England's top order struggled during the third-Test defeat in Mohali after they won the toss on a good batting pitch and Cook and Jennings overcame some early worries here to keep England on track.

Cook's dismissal, stumped as he moved down the wicket to Ravindra Jadeja, was uncharacteristic but showed England's change in mindset when it came to playing spin, and India's slow bowlers were stunted during the afternoon session.

After Joe Root had fallen, superbly caught at slip by Virat Kohli for 21, Moeen looked frenetic at the crease. However, once he settled he looked in good touch, lofting Jadeja high into the crowd for six before falling on the sweep.